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Friday, June 16, 2023

Epidemiology of cancer

From Wikipedia, the free encyclopedia
 
The age-adjusted death rate from cancer per 100,000 inhabitants in 2004.
  no data
  less than 55
  55–80
  80–105
  105–130
  130–155
  155–180
  180–205
  205–230
  230–255
  255–280
  280–305
  more than 305
Age adjusted, new cases of cancer in 2017

The epidemiology of cancer is the study of the factors affecting cancer, as a way to infer possible trends and causes. The study of cancer epidemiology uses epidemiological methods to find the cause of cancer and to identify and develop improved treatments.

This area of study must contend with problems of lead time bias and length time bias. Lead time bias is the concept that early diagnosis may artificially inflate the survival statistics of a cancer, without really improving the natural history of the disease. Length bias is the concept that slower growing, more indolent tumors are more likely to be diagnosed by screening tests, but improvements in diagnosing more cases of indolent cancer may not translate into better patient outcomes after the implementation of screening programs. A related concern is overdiagnosis, the tendency of screening tests to diagnose diseases that may not actually impact the patient's longevity. This problem especially applies to prostate cancer and PSA screening.

Some cancer researchers have argued that negative cancer clinical trials lack sufficient statistical power to discover a benefit to treatment. This may be due to fewer patients enrolled in the study than originally planned.

Organizations

State and regional cancer registries are organizations that abstract clinical data about cancer from patient medical records. These institutions provide information to state and national public health groups to help track trends in cancer diagnosis and treatment. One of the largest and most important cancer registries is Surveillance Epidemiology and End Results (SEER), administered by the US Federal government.

Health information privacy concerns have led to the restricted use of cancer registry data in the United States Department of Veterans Affairs and other institutions. The American Cancer Society predicts that approximately 1,690,000 new cancer cases will be diagnosed and 577,000 Americans will ultimately die of cancer in 2012.

Studies

Observational epidemiological studies that show associations between risk factors and specific cancers mostly serve to generate hypotheses about potential interventions that could reduce cancer incidence or morbidity. Randomized controlled trials then test whether hypotheses generated by epidemiological studies and laboratory research actually result in reduced cancer incidence and mortality. In many cases, findings from observational epidemiological studies are not confirmed by randomized controlled trials.

Risk factors

The approximate relative levels of the preventable causes of cancer in the United States, taken from the article Cancer prevention.

The most significant risk factor is age. According to cancer researcher Robert A. Weinberg, "If we lived long enough, sooner or later we all would get cancer." Essentially all of the increase in cancer rates between prehistoric times and people who died in England between 1901 and 1905 is due to increased lifespans.

Although the age-related increase in cancer risk is well-documented, the age-related patterns of cancer are complex. Some types of cancer, like testicular cancer, have early-life incidence peaks, for reasons unknown. Besides, the rate of age-related increase in cancer incidence varies between cancer types with, for instance, prostate cancer incidence accelerating much faster than brain cancer. It has been proposed that the age distribution of cancer incidence can be viewed as the distribution of probability to accumulate the required number of driver events by the given age.

Over a third of cancer deaths worldwide (and about 75-80% of cancers in the United States) are due to potentially modifiable risk factors. The leading modifiable risk factors worldwide are:

  • tobacco smoking, which is strongly associated with lung cancer, mouth, and throat cancer;
  • drinking alcohol, which is associated with a small increase in oral, esophageal, breast, liver and other cancers;
  • a diet low in fruit and vegetables,
  • physical inactivity, which is associated with increased risk of colon, breast, and possibly other cancers
  • obesity, which is associated with colon, breast, endometrial, and possibly other cancers
  • sexual transmission of human papillomavirus, which causes cervical cancer and some forms of anal cancer, vaginal cancer, vulvar cancer, penile cancer, rectal cancer, and oropharyngeal cancer.

Men with cancer are twice as likely as women to have a modifiable risk factor for their disease.

Other lifestyle and environmental factors known to affect cancer risk (either beneficially or detrimentally) include the use of exogenous hormones (e.g., hormone replacement therapy causes breast cancer), exposure to ionizing radiation and ultraviolet radiation, and certain occupational and chemical exposures. A Western diet is associated with increased exposure of the gastrointestinal tract to bile acids that are produced by the body to digest fatty foods. Bile acids are likely endogenous etiologic agents in gastrointestinal cancer.

Every year, at least 200,000 people die worldwide from cancer related to their workplace. Millions of workers run the risk of developing cancers such as pleural and peritoneal mesothelioma from inhaling asbestos fibers, or leukemia from exposure to benzene at their workplaces. Currently, most cancer deaths caused by occupational risk factors occur in the developed world. It is estimated that approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the U.S. are attributable to occupation.

Rates and mortality

New cancer diagnosis in the England in 2012

In the U.S. cancer is second only to cardiovascular disease as the leading cause of death; in the UK it is the leading cause of death. In many developing countries cancer incidence (insofar as this can be measured) appears much lower, most likely because of the higher death rates due to infectious disease or injury. With the increased control over malaria and tuberculosis in some Third World countries, incidence of cancer is expected to rise; in the Eastern Mediterranean region, for example, cancer incidence is expected to increase by 100% to 180% in the next 15 years due to increases in life expectancy, an increasing proportion of elderly people, and the successful control of childhood disease. This is termed the epidemiologic transition in epidemiological terminology.

Cancer epidemiology closely mirrors risk factor spread in various countries. Hepatocellular carcinoma (liver cancer) is rare in the West but is the main cancer in China and neighbouring countries, most likely due to the endemic presence of hepatitis B and aflatoxin in that population. Similarly, with tobacco smoking becoming more common in various Third World countries, lung cancer incidence has increased in a parallel fashion.

India

According to the National Cancer Registry Programme of the India Council of Medical Research (ICMR), more than 1300 Indians die every day due to cancer. Between 2012 and 2014, the mortality rate due to cancer increased by approximately 6%. In 2012, there were 478,180 deaths out of 2,934,314 cases reported. In 2013 there were 465,169 deaths out of 3,016,628 cases. In 2014, 491,598 people died in out of 2,820,179 cases. According to the Population Cancer Registry of Indian Council of Medical Research, the incidence and mortality of cancer is highest in the north-eastern region of the country. Breast cancer is the most common, and stomach cancer is the leading cause of death by cancer for the population as a whole. Breast cancer and lung cancer kill the most women and men respectively.

Canada

In Canada, as of 2007, cancer is the number one cause of death, contributing to 29.6% of all deaths in the country. The second highest cause of death is cardiovascular diseases resulting in 21.5% of deaths. As of 2011, prostate cancer was the most common form of cancer among males (about 28% of all new cases) and breast cancer the most common in females (also about 28% of all new cases).

The leading cause of death in both males and females is lung cancer, which contributes to 26.8% of all cancer deaths. Statistics indicate that between the ages of 20 and 50 years, the incidence rate of cancer is higher amongst women whereas after 50 years of age, the incidence rate increases in men. Predictions by the Canadian Cancer Society indicate that with time, there will be an increase in the rates of incidence of cancer for both males and females. Cancer will thus continue to be a persistent issue in years to come.

United States

In the United States, cancer is responsible for 25% of all deaths with 30% of these from lung cancer. The most commonly occurring cancer in men is prostate cancer (about 25% of new cases) and in women is breast cancer (also about 25%). Cancer can occur in children and adolescents, but it is uncommon (about 150 cases per million in the U.S.), with leukemia the most common. In the first year of life the incidence is about 230 cases per million in the U.S., with the most common being neuroblastoma. Data from 2004 to 2008 in the United States indicates that the overall age-adjusted incidence of cancer was approximately 460 per 100,000 men and women per year.

Cancer is responsible for about 25% of all deaths in the U.S., and is a major public health problem in many parts of the world. The statistics below are estimates for the U.S. in 2008, and may vary substantially in other countries. They exclude basal and squamous cell skin cancers, and carcinoma in situ in locations other than the urinary bladder. As seen, breast/prostate cancer, lung cancer and colorectal cancer are responsible for approximately half of cancer incidence. The same applies for cancer mortality, but with lung cancer replacing breast/prostate cancer as the main cause.

In 2016, an estimated 1,685,210 new cases of cancer will be diagnosed in the United States and 595,690 people will die from the disease.

Male
Female
most common (by occurrence) most common (by mortality) most common (by occurrence) most common (by mortality)
prostate cancer (25%) lung cancer (31%) breast cancer (26%) lung cancer (26%)
lung cancer (15%) prostate cancer (10%) lung cancer (14%) breast cancer (15%)
colorectal cancer (10%) colorectal cancer (8%) colorectal cancer (10%) colorectal cancer (9%)
bladder cancer (7%) pancreatic cancer (6%) endometrial cancer (7%) pancreatic cancer (6%)
non-Hodgkin lymphoma (5%) liver & intrahepatic bile duct (4%) non-Hodgkin lymphoma (4%) ovarian cancer (6%)
skin melanoma (5%) leukemia (4%) thyroid cancer (4%) non-Hodgkin lymphoma (3%)
kidney cancer (4%) esophageal cancer (4%) Skin melanoma (4%) leukemia (3%)
oral and pharyngeal cancer (3%) bladder cancer (3%) ovarian cancer (3%) uterine cancer (3%)
leukemia (3%) non-Hodgkin lymphoma (3%) kidney cancer (3%) liver & intrahepatic bile duct (2%)
pancreatic cancer (3%) kidney cancer (3%) leukemia (3%) brain and other nervous system (2%)
other (20%) other (24%) other (22%) other (25%)

Incidence of a second cancer in survivors

In the developed world, one in three people will develop cancer during their lifetimes. If all cancer patients survived and cancer occurred randomly, the normal lifetime odds of developing a second primary cancer (not the first cancer spreading to a new site) would be one in nine. However, cancer survivors have an increased risk of developing a second primary cancer, and the odds are about two in nine. About half of these second primaries can be attributed to the normal one-in-nine risk associated with random chance.

The increased risk is believed to be primarily due to the same risk factors that produced the first cancer, such as the person's genetic profile, alcohol and tobacco use, obesity, and environmental exposures, and partly due, in some cases, to the treatment for the first cancer, which might have included mutagenic chemotherapeutic drugs or radiation. Cancer survivors may also be more likely to comply with recommended screening, and thus may be more likely than average to detect cancers.

Children

Childhood cancer and cancer in adolescents is rare (about 150 cases per million yearly in the US). Leukemia (usually acute lymphoblastic leukemia) is the most common cancer in children aged 1–14 in the U.S., followed by the central nervous system cancers, neuroblastoma, Wilms' tumor, and non-Hodgkin's lymphoma. Statistics from the SEER program of the US NCI demonstrate that childhood cancers increased 19% between 1975 and 1990, mainly due to an increased incidence in acute leukemia. Since 1990, incidence rates have decreased.

Infants

The age of peak incidence of cancer in children occurs during the first year of life, in infants. The average annual incidence in the United States, 1975–1995, was 233 per million infants. Several estimates of incidence exist. According to SEER, in the United States:

  • Neuroblastoma comprised 28% of infant cancer cases and was the most common malignancy among these young children (65 per million infants).
  • The leukemias as a group (41 per million infants) represented the next most common type of cancer, comprising 17% of all cases.
  • Central nervous system malignancies comprised 13% of infant cancer, with an average annual incidence rate of nearly 30 per million infants.
  • The average annual incidence rates for malignant germ cell and malignant soft tissue tumors were essentially the same at 15 per million infants. Each comprised about 6% of infant cancer.

Teratoma (a germ cell tumor) often is cited as the most common tumor in this age group, but most teratomas are surgically removed while still benign, hence not necessarily cancer. Prior to the widespread routine use of prenatal ultrasound examinations, the incidence of sacrococcygeal teratomas diagnosed at birth was 25 to 29 per million births.

Female and male infants have essentially the same overall cancer incidence rates, a notable difference compared to older children.

White infants have higher cancer rates than black infants. Leukemias accounted for a substantial proportion of this difference: the average annual rate for white infants (48.7 per million) was 66% higher than for black infants (29.4 per million).

Relative survival for infants is very good for neuroblastoma, Wilms' tumor and retinoblastoma, and fairly good (80%) for leukemia, but not for most other types of cancer.

Cancer cell

From Wikipedia, the free encyclopedia

Cancer cells are cells that divide continually, forming solid tumors or flooding the blood or lymph with abnormal cells. Cell division is a normal process used by the body for growth and repair. A parent cell divides to form two daughter cells, and these daughter cells are used to build new tissue or to replace cells that have died because of aging or damage. Healthy cells stop dividing when there is no longer a need for more daughter cells, but cancer cells continue to produce copies. They are also able to spread from one part of the body to another in a process known as metastasis.

Classification

There are different categories of cancer cell, defined according to the cell type from which they originate.

Histology

Histological features of normal cells and cancer cells

Cancer cells have distinguishing histological features visible under the microscope. The nucleus is often large and irregular, and the cytoplasm may also display abnormalities.

Nucleus

The shape, size, protein composition, and texture of the nucleus are often altered in malignant cells. The nucleus may acquire grooves, folds or indentations, chromatin may aggregate or disperse, and the nucleolus can become enlarged. In normal cells, the nucleus is often round or solid in shape, but in cancer cells the outline is often irregular. Different combinations of abnormalities are characteristic of different cancer types, to the extent that nuclear appearance can be used as a marker in cancer diagnostics and staging.

Causes

Cancer cells are created when the genes responsible for regulating cell division are damaged. Carcinogenesis is caused by mutation and epimutation of the genetic material of normal cells, which upsets the normal balance between proliferation and cell death. This results in uncontrolled cell division in the body. The uncontrolled and often rapid proliferation of cells can lead to benign or malignant tumours (cancer). Benign tumors do not spread to other parts of the body or invade other tissues. Malignant tumors can invade other organs, spread to distant locations (metastasis) and become life-threatening.

More than one mutation is necessary for carcinogenesis. In fact, a series of several mutations to certain classes of genes is usually required before a normal cell will transform into a cancer cell.

Damage to DNA can be caused by exposure to radiation, chemicals, and other environmental sources, but mutations also accumulate naturally over time through uncorrected errors in DNA transcription, making age another risk factor. Oncoviruses can cause certain types of cancer, and genetics are also known to play a role.

Stem cell research suggests that excess SP2 protein may turn stem cells into cancer cells. However, a lack of particular co-stimulated molecules that aid in the way antigens react with lymphocytes can impair the natural killer cells' function, ultimately leading to cancer.

DNA repair and mutation

When a cell is deficient in the capacity to repair DNA damages, such damages tend to be retained within the cell at an increased level. These damages, upon replication of the cell’s DNA, may cause replication errors, including mutations that lead to cancer. Numerous inherited DNA repair disorders have been described that increase cancer risk (see Wikipedia article DNA repair-deficiency disorder). In addition, particular DNA repair enzymes have been found to be deficient in multiple cancers. For example, deficient expression of the DNA repair enzyme O-6-methylguanine-DNA methyltransferase is observed in several different kinds of cancer (see Wikipedia article O-6-methylguanine-DNA methyltransferase). Although a DNA repair deficiency can predispose a cell lineage to develop cancer, increased (rather than decreased) expression of a repair capability may also emerge in the progression of cancer cell lineages, and this capability may be clinically important as reviewed by Lingg et al. For instance, the DNA repair gene DMC1 encodes a protein that is normally expressed only in cells undergoing meiosis where it helps maintain an undamaged germ-line. However, DMC1 is also expressed in various cancer cell lines including cervical, breast, and lymphoma cancer cell lines. Expression of meiotic DNA repair genes such as DMC1 may promote tumor cell growth by dealing with endogenous DNA damage within the tumor, and may also diminish the effectiveness of anticancer therapy, such as radiation therapy.

Pathology

Cells playing roles in the immune system, such as T-cells, are thought to use a dual receptor system when they determine whether or not to kill sick or damaged human cells. If a cell is under stress, turning into tumors, or infected, molecules including MIC-A and MIC-B are produced so that they can attach to the surface of the cell. These work to help macrophages detect and kill cancer cells.

Discovery

Early evidence of human cancer can be interpreted from Egyptian papers (1538 BCE) and mummified remains. In 2016, a 1.7 million year old osteosarcoma was reported by Edward John Odes (a doctoral student in Anatomical Sciences from Witwatersrand Medical School, South Africa) and colleagues, representing the oldest documented malignant hominin cancer.

The understanding of cancer was significantly advanced during the Renaissance period and in to the Age of Discovery. Sir Rudolf Virchow, a German biologist and politician, studied microscopic pathology, and linked his observations to illness. He is described as "the founder of cellular pathology". In 1845, Virchow and John Hughes Bennett independently observed abnormal increase in white blood cells in patients. Virchow correctly identified the condition as blood disease, and named it leukämie in 1847 (later anglicised to leukemia). In 1857, he was the first to describe a type of tumour called chordoma that originated from the clivus (at the base of the skull).

Telomerase

Cancer cells have unique features that make them "immortal" according to some researchers. The enzyme telomerase is used to extend the cancer cell's life span. While the telomeres of most cells shorten after each division, eventually causing the cell to die, telomerase extends the cell's telomeres. This is a major reason that cancer cells can accumulate over time, creating tumors.

Cancer stem cells and drug resistance

A diagram illustrating the distinction between cancer stem cell targeted and conventional cancer therapies

Scientists have discovered a molecule on the surface of tumors that appears to promote drug resistance—by converting the tumor cells back into a stem cell-like state.

When the tumor cells began to exhibit drug resistance, the cells were simultaneously transforming into a stem cell-like state, which made them impervious to the drugs. It appeared that the treatment itself was driving this transformation by activating a specific molecular pathway. Luckily, several existing drugs, such as Bortezomib for example, can attack this pathway and reverse the cellular transformation, thus 're-sensitizing' the tumor to treatment.

Treatment

In February 2019, medical scientists announced that iridium attached to albumin, creating a photosensitized molecule, can penetrate cancer cells and, after being irradiated with light (a process called photodynamic therapy), destroy the cancer cells.

Neoplasm

From Wikipedia, the free encyclopedia
 
Neoplasm
Other namesTumor, tumour, carcinocytes
Colon cancer 2.jpg
Colectomy specimen containing a malignant neoplasm, namely an invasive example of colorectal cancer (the crater-like, reddish, irregularly shaped tumor at top-center)
SpecialtyOncology
SymptomsLump
ComplicationsCancer
CausesRadiation, environmental factor, certain infections

A neoplasm (/ˈn.ˌplæzəm, ˈn.ə-/) is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed. This abnormal growth usually forms a mass, when it may be called a tumour or tumor.

ICD-10 classifies neoplasms into four main groups: benign neoplasms, in situ neoplasms, malignant neoplasms, and neoplasms of uncertain or unknown behavior. Malignant neoplasms are also simply known as cancers and are the focus of oncology.

Prior to the abnormal growth of tissue, as neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia. However, metaplasia or dysplasia does not always progress to neoplasia and can occur in other conditions as well. The word is from Ancient Greek νέος- neo 'new' and πλάσμα plasma 'formation, creation'.

Types

A neoplasm can be benign, potentially malignant, or malignant (cancer).

  • Benign tumors include uterine fibroids, osteophytes and melanocytic nevi (skin moles). They are circumscribed and localized and do not transform into cancer.
  • Potentially-malignant neoplasms include carcinoma in situ. They are localised, do not invade and destroy but in time, may transform into a cancer.
  • Malignant neoplasms are commonly called cancer. They invade and destroy the surrounding tissue, may form metastases and, if untreated or unresponsive to treatment, will generally prove fatal.
  • Secondary neoplasm refers to any of a class of cancerous tumor that is either a metastatic offshoot of a primary tumor, or an apparently unrelated tumor that increases in frequency following certain cancer treatments such as chemotherapy or radiotherapy.
  • Rarely there can be a metastatic neoplasm with no known site of the primary cancer and this is classed as a cancer of unknown primary origin.

Clonality

Neoplastic tumors are often heterogeneous and contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of neoplastic cells. These cells are presumed to be monoclonal – that is, they are derived from the same cell, and all carry the same genetic or epigenetic anomaly – evident of clonality. For lymphoid neoplasms, e.g. lymphoma and leukemia, clonality is proven by the amplification of a single rearrangement of their immunoglobulin gene (for B cell lesions) or T cell receptor gene (for T cell lesions). The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic.

It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. Therefore, clonality is not required in the definition of neoplasia.

Neoplasm vs. tumor

The word tumor or tumour comes from the Latin word for swelling, which is one of the cardinal signs of inflammation. The word originally referred to any form of swelling, neoplastic or not. In modern English, tumor is used as a synonym for neoplasm (a solid or fluid-filled cystic lesion that may or may not be formed by an abnormal growth of neoplastic cells) that appears enlarged in size. Some neoplasms do not form a tumor - these include leukemia and most forms of carcinoma in situ. Tumor is also not synonymous with cancer. While cancer is by definition malignant, a tumor can be benign, precancerous, or malignant.

The terms mass and nodule are often used synonymously with tumor. Generally speaking, however, the term tumor is used generically, without reference to the physical size of the lesion. More specifically, the term mass is often used when the lesion has a maximal diameter of at least 20 millimeters (mm) in greatest direction, while the term nodule is usually used when the size of the lesion is less than 20 mm in its greatest dimension (25.4 mm = 1 inch).

Causes

Neoplastic tumor of the cheek skin, here a benign neoplasm of the sweat glands called hidradenoma, which is not solid but is fluid-filled
 
Diagram illustrating benign neoplasms, namely fibroids of the uterus

Tumors in humans occur as a result of accumulated genetic and epigenetic alterations within single cells, which cause the cell to divide and expand uncontrollably. A neoplasm can be caused by an abnormal proliferation of tissues, which can be caused by genetic mutations. Not all types of neoplasms cause a tumorous overgrowth of tissue, however (such as leukemia or carcinoma in situ) and similarities between neoplasmic growths and regenerative processes, e.g., dedifferentiation and rapid cell proliferation, have been pointed out.

Tumor growth has been studied using mathematics and continuum mechanics. Vascular tumors such as hemangiomas and lymphangiomas (formed from blood or lymph vessels) are thus looked at as being amalgams of a solid skeleton formed by sticky cells and an organic liquid filling the spaces in which cells can grow. Under this type of model, mechanical stresses and strains can be dealt with and their influence on the growth of the tumor and the surrounding tissue and vasculature elucidated. Recent findings from experiments that use this model show that active growth of the tumor is restricted to the outer edges of the tumor and that stiffening of the underlying normal tissue inhibits tumor growth as well.

Benign conditions that are not associated with an abnormal proliferation of tissue (such as sebaceous cysts) can also present as tumors, however, but have no malignant potential. Breast cysts (as occur commonly during pregnancy and at other times) are another example, as are other encapsulated glandular swellings (thyroid, adrenal gland, pancreas).

Encapsulated hematomas, encapsulated necrotic tissue (from an insect bite, foreign body, or other noxious mechanism), keloids (discrete overgrowths of scar tissue) and granulomas may also present as tumors.

Discrete localized enlargements of normal structures (ureters, blood vessels, intrahepatic or extrahepatic biliary ducts, pulmonary inclusions, or gastrointestinal duplications) due to outflow obstructions or narrowings, or abnormal connections, may also present as a tumor. Examples are arteriovenous fistulae or aneurysms (with or without thrombosis), biliary fistulae or aneurysms, sclerosing cholangitis, cysticercosis or hydatid cysts, intestinal duplications, and pulmonary inclusions as seen with cystic fibrosis. It can be dangerous to biopsy a number of types of tumor in which the leakage of their contents would potentially be catastrophic. When such types of tumors are encountered, diagnostic modalities such as ultrasound, CT scans, MRI, angiograms, and nuclear medicine scans are employed prior to (or during) biopsy or surgical exploration/excision in an attempt to avoid such severe complications.

Malignant neoplasms

DNA damage

The central role of DNA damage and epigenetic defects in DNA repair genes in malignant neoplasms

DNA damage is considered to be the primary underlying cause of malignant neoplasms known as cancers. Its central role in progression to cancer is illustrated in the figure in this section, in the box near the top. (The central features of DNA damage, epigenetic alterations and deficient DNA repair in progression to cancer are shown in red.) DNA damage is very common. Naturally occurring DNA damages (mostly due to cellular metabolism and the properties of DNA in water at body temperatures) occur at a rate of more than 60,000 new damages, on average, per human cell, per day also see article DNA damage (naturally occurring) ]. Additional DNA damages can arise from exposure to exogenous agents. Tobacco smoke causes increased exogenous DNA damage, and these DNA damages are the likely cause of lung cancer due to smoking. UV light from solar radiation causes DNA damage that is important in melanoma. Helicobacter pylori infection produces high levels of reactive oxygen species that damage DNA and contributes to gastric cancer. Bile acids, at high levels in the colons of humans eating a high fat diet, also cause DNA damage and contribute to colon cancer. Katsurano et al. indicated that macrophages and neutrophils in an inflamed colonic epithelium are the source of reactive oxygen species causing the DNA damages that initiate colonic tumorigenesis. Some sources of DNA damage are indicated in the boxes at the top of the figure in this section.

Individuals with a germline mutation causing deficiency in any of 34 DNA repair genes (see article DNA repair-deficiency disorder) are at increased risk of cancer. Some germline mutations in DNA repair genes cause up to 100% lifetime chance of cancer (e.g., p53 mutations). These germline mutations are indicated in a box at the left of the figure with an arrow indicating their contribution to DNA repair deficiency.

About 70% of malignant neoplasms have no hereditary component and are called "sporadic cancers". Only a minority of sporadic cancers have a deficiency in DNA repair due to mutation in a DNA repair gene. However, a majority of sporadic cancers have deficiency in DNA repair due to epigenetic alterations that reduce or silence DNA repair gene expression. For example, of 113 sequential colorectal cancers, only four had a missense mutation in the DNA repair gene MGMT, while the majority had reduced MGMT expression due to methylation of the MGMT promoter region (an epigenetic alteration). Five reports present evidence that between 40% and 90% of colorectal cancers have reduced MGMT expression due to methylation of the MGMT promoter region.

Similarly, out of 119 cases of mismatch repair-deficient colorectal cancers that lacked DNA repair gene PMS2 expression, PMS2 was deficient in 6 due to mutations in the PMS2 gene, while in 103 cases PMS2 expression was deficient because its pairing partner MLH1 was repressed due to promoter methylation (PMS2 protein is unstable in the absence of MLH1). In the other 10 cases, loss of PMS2 expression was likely due to epigenetic overexpression of the microRNA, miR-155, which down-regulates MLH1.

In further examples, epigenetic defects were found at frequencies of between 13%-100% for the DNA repair genes BRCA1, WRN, FANCB, FANCF, MGMT, MLH1, MSH2, MSH4, ERCC1, XPF, NEIL1 and ATM. These epigenetic defects occurred in various cancers (e.g. breast, ovarian, colorectal and head and neck). Two or three deficiencies in expression of ERCC1, XPF or PMS2 occur simultaneously in the majority of the 49 colon cancers evaluated by Facista et al. Epigenetic alterations causing reduced expression of DNA repair genes is shown in a central box at the third level from the top of the figure in this section, and the consequent DNA repair deficiency is shown at the fourth level.

When expression of DNA repair genes is reduced, DNA damages accumulate in cells at a higher than normal level, and these excess damages cause increased frequencies of mutation or epimutation. Mutation rates strongly increase in cells defective in DNA mismatch repair or in homologous recombinational repair (HRR).

During repair of DNA double strand breaks, or repair of other DNA damages, incompletely cleared sites of repair can cause epigenetic gene silencing. DNA repair deficiencies (level 4 in the figure) cause increased DNA damages (level 5 in the figure) which result in increased somatic mutations and epigenetic alterations (level 6 in the figure).

Field defects, normal appearing tissue with multiple alterations (and discussed in the section below), are common precursors to development of the disordered and improperly proliferating clone of tissue in a malignant neoplasm. Such field defects (second level from bottom of figure) may have multiple mutations and epigenetic alterations.

Once a cancer is formed, it usually has genome instability. This instability is likely due to reduced DNA repair or excessive DNA damage. Because of such instability, the cancer continues to evolve and to produce sub clones. For example, a renal cancer, sampled in 9 areas, had 40 ubiquitous mutations, demonstrating tumor heterogeneity (i.e. present in all areas of the cancer), 59 mutations shared by some (but not all areas), and 29 "private" mutations only present in one of the areas of the cancer.

Field defects

Longitudinally opened freshly resected colon segment showing a cancer and four polyps, plus a schematic diagram indicating a likely field defect (a region of tissue that precedes and predisposes to the development of cancer) in this colon segment. The diagram indicates sub-clones and sub-sub-clones that were precursors to the tumors.

Various other terms have been used to describe this phenomenon, including "field effect", "field cancerization", and "field carcinogenesis". The term "field cancerization" was first used in 1953 to describe an area or "field" of epithelium that has been preconditioned by (at that time) largely unknown processes so as to predispose it towards development of cancer. Since then, the terms "field cancerization" and "field defect" have been used to describe pre-malignant tissue in which new cancers are likely to arise.

Field defects are important in progression to cancer. However, in most cancer research, as pointed out by Rubin "The vast majority of studies in cancer research has been done on well-defined tumors in vivo, or on discrete neoplastic foci in vitro. Yet there is evidence that more than 80% of the somatic mutations found in mutator phenotype human colorectal tumors occur before the onset of terminal clonal expansion. Similarly, Vogelstein et al. point out that more than half of somatic mutations identified in tumors occurred in a pre-neoplastic phase (in a field defect), during growth of apparently normal cells. Likewise, epigenetic alterations present in tumors may have occurred in pre-neoplastic field defects.

An expanded view of field effect has been termed "etiologic field effect", which encompasses not only molecular and pathologic changes in pre-neoplastic cells but also influences of exogenous environmental factors and molecular changes in the local microenvironment on neoplastic evolution from tumor initiation to patient death.

In the colon, a field defect probably arises by natural selection of a mutant or epigenetically altered cell among the stem cells at the base of one of the intestinal crypts on the inside surface of the colon. A mutant or epigenetically altered stem cell may replace the other nearby stem cells by natural selection. Thus, a patch of abnormal tissue may arise. The figure in this section includes a photo of a freshly resected and lengthwise-opened segment of the colon showing a colon cancer and four polyps. Below the photo, there is a schematic diagram of how a large patch of mutant or epigenetically altered cells may have formed, shown by the large area in yellow in the diagram. Within this first large patch in the diagram (a large clone of cells), a second such mutation or epigenetic alteration may occur so that a given stem cell acquires an advantage compared to other stem cells within the patch, and this altered stem cell may expand clonally forming a secondary patch, or sub-clone, within the original patch. This is indicated in the diagram by four smaller patches of different colors within the large yellow original area. Within these new patches (sub-clones), the process may be repeated multiple times, indicated by the still smaller patches within the four secondary patches (with still different colors in the diagram) which clonally expand, until stem cells arise that generate either small polyps or else a malignant neoplasm (cancer).

In the photo, an apparent field defect in this segment of a colon has generated four polyps (labeled with the size of the polyps, 6mm, 5mm, and two of 3mm, and a cancer about 3 cm across in its longest dimension). These neoplasms are also indicated, in the diagram below the photo, by 4 small tan circles (polyps) and a larger red area (cancer). The cancer in the photo occurred in the cecal area of the colon, where the colon joins the small intestine (labeled) and where the appendix occurs (labeled). The fat in the photo is external to the outer wall of the colon. In the segment of colon shown here, the colon was cut open lengthwise to expose the inner surface of the colon and to display the cancer and polyps occurring within the inner epithelial lining of the colon.

If the general process by which sporadic colon cancers arise is the formation of a pre-neoplastic clone that spreads by natural selection, followed by formation of internal sub-clones within the initial clone, and sub-sub-clones inside those, then colon cancers generally should be associated with, and be preceded by, fields of increasing abnormality reflecting the succession of premalignant events. The most extensive region of abnormality (the outermost yellow irregular area in the diagram) would reflect the earliest event in formation of a malignant neoplasm.

In experimental evaluation of specific DNA repair deficiencies in cancers, many specific DNA repair deficiencies were also shown to occur in the field defects surrounding those cancers. The Table, below, gives examples for which the DNA repair deficiency in a cancer was shown to be caused by an epigenetic alteration, and the somewhat lower frequencies with which the same epigenetically caused DNA repair deficiency was found in the surrounding field defect.

Some of the small polyps in the field defect shown in the photo of the opened colon segment may be relatively benign neoplasms. Of polyps less than 10mm in size, found during colonoscopy and followed with repeat colonoscopies for 3 years, 25% were unchanged in size, 35% regressed or shrank in size while 40% grew in size.

Genome instability

Cancers are known to exhibit genome instability or a mutator phenotype. The protein-coding DNA within the nucleus is about 1.5% of the total genomic DNA. Within this protein-coding DNA (called the exome), an average cancer of the breast or colon can have about 60 to 70 protein altering mutations, of which about 3 or 4 may be "driver" mutations, and the remaining ones may be "passenger" mutations. However, the average number of DNA sequence mutations in the entire genome (including non-protein-coding regions) within a breast cancer tissue sample is about 20,000. In an average melanoma tissue sample (where melanomas have a higher exome mutation frequency) the total number of DNA sequence mutations is about 80,000. This compares to the very low mutation frequency of about 70 new mutations in the entire genome between generations (parent to child) in humans.

The high frequencies of mutations in the total nucleotide sequences within cancers suggest that often an early alteration in the field defects giving rise to a cancer (e.g. yellow area in the diagram in this section) is a deficiency in DNA repair. The large field defects surrounding colon cancers (extending to at about 10 cm on each side of a cancer) were shown by Facista et al. to frequently have epigenetic defects in 2 or 3 DNA repair proteins (ERCC1, XPF or PMS2) in the entire area of the field defect. Deficiencies in DNA repair cause increased mutation rates. A deficiency in DNA repair, itself, can allow DNA damages to accumulate, and error-prone translesion synthesis past some of those damages may give rise to mutations. In addition, faulty repair of these accumulated DNA damages may give rise to epimutations. These new mutations or epimutations may provide a proliferative advantage, generating a field defect. Although the mutations/epimutations in DNA repair genes do not, themselves, confer a selective advantage, they may be carried along as passengers in cells when the cells acquire additional mutations/epimutations that do provide a proliferative advantage.

Etymology

The term neoplasm is a synonym of tumor. Neoplasia denotes the process of the formation of neoplasms/tumors, and the process is referred to as a neoplastic process. The word neoplastic itself comes from Greek neo 'new' and plastic 'formed, molded'.

The term tumor derives from the Latin noun tumor 'a swelling', ultimately from the verb tumēre 'to swell'. In the British Commonwealth, the spelling tumour is commonly used, whereas in the U.S. the word is usually spelled tumor.

In its medical sense, tumor has traditionally meant an abnormal swelling of the flesh. The Roman medical encyclopedist Celsus (c. 30 BC–38 AD) described the four cardinal signs of acute inflammation as tumor, dolor, calor, and rubor (swelling, pain, increased heat, and redness). (His treatise, De Medicina, was the first medical book printed in 1478 following the invention of the movable-type printing press.)

In contemporary English, the word tumor is often used as a synonym for a cystic (liquid-filled) growth or solid neoplasm (cancerous or non-cancerous), with other forms of swelling often referred to as "swellings".

Related terms occur commonly in the medical literature, where the nouns tumefaction and tumescence (derived from the adjective tumescent) are current medical terms for non-neoplastic swelling. This type of swelling is most often caused by inflammation caused by trauma, infection, and other factors.

Tumors may be caused by conditions other than an overgrowth of neoplastic cells, however. Cysts (such as sebaceous cysts) are also referred to as tumors, even though they have no neoplastic cells. This is standard in medical-billing terminology (especially when billing for a growth whose pathology has yet to be determined).

Food and Drug Administration

From Wikipedia, the free encyclopedia
 
Food and Drug Administration
Logo of the United States Food and Drug Administration.svg
Agency overview
FormedJune 30, 1906; 116 years ago
Preceding agencies
  • Food, Drug, and Insecticide Administration (July 1927 to July 1930)
  • Bureau of Chemistry, USDA (July 1901 through July 1927)
  • Division of Chemistry, USDA (established 1862)
JurisdictionFederal government of the United States
HeadquartersWhite Oak Campus
10903 New Hampshire Avenue
Silver Spring, Maryland 20993
39°02′07″N 76°58′59″W
Employees18,000 (2022)
Annual budgetUS$6.5 billion (2022)
Agency executives
Parent agencyDepartment of Health and Human Services
Child agencies
Websitefda.gov

The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, prescription and over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, animal foods & feed and veterinary products.

The FDA's primary focus is enforcement of the Federal Food, Drug, and Cosmetic Act (FD&C), but the agency also enforces other laws, notably Section 361 of the Public Health Service Act, as well as associated regulations. Much of this regulatory-enforcement work is not directly related to food or drugs, but involves such things as regulating lasers, cellular phones, and condoms, as well as control of disease in contexts varying from household pets to human sperm donated for use in assisted reproduction.

The FDA is led by the Commissioner of Food and Drugs, appointed by the President with the advice and consent of the Senate. The Commissioner reports to the Secretary of Health and Human Services. Robert Califf is the current commissioner, as of 17 February 2022.

The FDA has its headquarters in unincorporated White Oak, Maryland. The agency also has 223 field offices and 13 laboratories located throughout the 50 states, the United States Virgin Islands, and Puerto Rico. In 2008, the FDA began to post employees to foreign countries, including China, India, Costa Rica, Chile, Belgium, and the United Kingdom.

FDA Building 31 houses the Office of the Commissioner and the Office of Regulatory Department of Health and Human Services. The agency consists of fourteen Centers and Offices.

Organizational structure

Location

FDA Building 66 houses the Center for Devices and Radiological Health.

Headquarters

FDA headquarters facilities are currently located in Montgomery County and Prince George's County, Maryland.

White Oak Federal Research Center

Since 1990, the FDA has had employees and facilities on 130 acres (53 hectares) of the White Oak Federal Research Center in the White Oak area of Silver Spring, Maryland. In 2001, the General Services Administration (GSA) began new construction on the campus to consolidate the FDA's 25 existing operations in the Washington metropolitan area, its headquarters in Rockville, and several fragmented office buildings. The first building, the Life Sciences Laboratory, was dedicated and opened with 104 employees in December 2003. As of December 2018, the FDA campus has a population of 10,987 employees housed in approximately 3,800,000 square feet (350,000 square metres) of space, divided into ten office and four laboratory buildings. The campus houses the Office of the Commissioner (OC), the Office of Regulatory Affairs (ORA),  the Center for Drug Evaluation and Research (CDER), the Center for Devices and Radiological Health (CDRH), the Center for Biologics Evaluation and Research (CBER) and offices for the Center for Veterinary Medicine (CVM).

With the passing of the FDA Reauthorization Act of 2017, the FDA is projecting a 64% increase in employees to 18,000 over the next 15 years, and would like to add approximately 1,600,000 square feet (150,000 square metres) of office and special use space to their existing facilities. The National Capital Planning Commission approved a new master plan for this expansion in December 2018, and construction is expected to be completed by 2035, dependent on GSA appropriations.

Field locations

The Arkansas Laboratory in Jefferson, Arkansas is the headquarters of the National Center for Toxicological Research.

Office of Regulatory Affairs

The Office of Regulatory Affairs is considered the agency's "eyes and ears," conducting the vast majority of the FDA's work in the field. Its employees, known as Consumer Safety Officers, or more commonly known simply as investigators, inspect production and warehousing facilities, investigate complaints, illnesses, or outbreaks, and review documentation in the case of medical devices, drugs, biological products, and other items where it may be difficult to conduct a physical examination or take a physical sample of the product. The Office of Regulatory Affairs is divided into five regions, which are further divided into 20 districts. Districts are based roughly on the geographic divisions of the Federal court system. Each district comprises a main district office and a number of Resident Posts, which are FDA remote offices that serve a particular geographic area. ORA also includes the Agency's network of regulatory laboratories, which analyze any physical samples taken. Though samples are usually food-related, some laboratories are equipped to analyze drugs, cosmetics, and radiation-emitting devices.

Office of Criminal Investigations

Jamaica, Queens, New York Regional Office - USFDA

The Office of Criminal Investigations was established in 1991 to investigate criminal cases. To do so, OCI employs approximately 200 Special Agents nationwide who, unlike ORA Investigators, are armed, have badges, and do not focus on technical aspects of the regulated industries. Rather, OCI agents pursue and develop cases when individuals and companies commit criminal actions, such as fraudulent claims or knowingly and willfully shipping known adulterated goods in interstate commerce. In many cases, OCI pursues cases involving violations of Title 18 of the United States Code (e.g., conspiracy, false statements, wire fraud, mail fraud), in addition to prohibited acts as defined in Chapter III of the FD&C Act. OCI Special Agents often come from other criminal investigations backgrounds, and frequently work closely with the Federal Bureau of Investigation, Assistant Attorney General, and even Interpol. OCI receives cases from a variety of sources—including ORA, local agencies, and the FBI, and works with ORA Investigators to help develop the technical and science-based aspects of a case.

Other locations

The FDA has a number of field offices across the United States, in addition to international locations in China, India, Europe, the Middle East, and Latin America.

Scope and funding

As of 2021, the FDA had responsibility for overseeing $2.7 trillion in food, medical, and tobacco products. Some 54% of its budget derives from the federal government, and 46% is covered by industry user fees for FDA services. For example, pharmaceutical firms pay fees to expedite drug reviews.

According to Forbes, the pharmaceutical firms provide 75% of the FDA's drug review budget.

Regulatory programs

Emergency approvals (EUA)

Emergency Use Authorization (EUA) is a mechanism that was created to facilitate the availability and use of medical countermeasures, including vaccines and personal protective equipment, during public health emergencies such as the Zika virus epidemic, the Ebola virus epidemic and the COVID-19 pandemic.

Regulations

The programs for safety regulation vary widely by the type of product, its potential risks, and the regulatory powers granted to the agency. For example, the FDA regulates almost every facet of prescription drugs, including testing, manufacturing, labeling, advertising, marketing, efficacy, and safety—yet FDA regulation of cosmetics focuses primarily on labeling and safety. The FDA regulates most products with a set of published standards enforced by a modest number of facility inspections. Inspection observations are documented on Form 483.

In June 2018, the FDA released a statement regarding new guidelines to help food and drug manufacturers "implement protections against potential attacks on the U.S. food supply". One of the guidelines includes the Intentional Adulteration (IA) rule, which requires strategies and procedures by the food industry to reduce the risk of compromise in facilities and processes that are significantly vulnerable.

The FDA also uses tactics of regulatory shaming, mainly through online publication of non-compliance, warning letters, and "shaming lists." Regulation by shaming harnesses firms' sensitivity to reputational damage. For example, in 2018, the agency published an online "black list," in which it named dozens of branded drug companies that are supposedly using unlawful or unethical means to attempt to impede competition from generic drug companies.

The FDA frequently works with other federal agencies, including the Department of Agriculture, the Drug Enforcement Administration, Customs and Border Protection, and the Consumer Product Safety Commission. They also often work with local and state government agencies in performing regulatory inspections and enforcement actions.

Food and dietary supplements

The regulation of food and dietary supplements by the Food and Drug Administration is governed by various statutes enacted by the United States Congress and interpreted by the FDA. Pursuant to the Federal Food, Drug, and Cosmetic Act and accompanying legislation, the FDA has authority to oversee the quality of substances sold as food in the United States, and to monitor claims made in the labeling of both the composition and the health benefits of foods.

The FDA subdivides substances that it regulates as food into various categories—including foods, food additives, added substances (human-made substances that are not intentionally introduced into food, but nevertheless end up in it), and dietary supplements. Dietary supplements or dietary ingredients include vitamins, minerals, herbs, amino acids, and. enzymes. Specific standards the FDA exercises differ from one category to the next. Furthermore, legislation had granted the FDA a variety of means to address violations of standards for a given substance category.

Under the Dietary Supplement Health and Education Act of 1994 (DSHEA), the FDA is responsible for ensuring that manufacturers and distributors of dietary supplements and dietary ingredients meet the current requirements. These manufacturers and distributors are not allowed to advertise their products in an adulterated way, and they are responsible for evaluating the safety and labeling of their product.

The FDA has a "Dietary Supplement Ingredient Advisory List" that includes ingredients that sometimes appear on dietary supplements but need further evaluation further. An ingredient is added to this list when it is excluded from use in a dietary supplement, does not appear to be an approved food additive or recognized as safe, and/or is subjected to the requirement for pre-market notification without having a satisfied requirement.

"FDA-Approved" vs. "FDA-Accepted in Food Processing"

The FDA does not approve applied coatings used in the food processing industry. There is no review process to approve the composition of nonstick coatings; nor does the FDA inspect or test these materials. Through their governing of processes, however, the FDA does have a set of regulations that cover the formulation, manufacturing, and use of nonstick coatings. Hence, materials like Polytetrafluoroethylene (Teflon) are not, and cannot be, considered as FDA Approved, rather, they are "FDA Compliant" or "FDA Acceptable".

Medical countermeasures (MCMs)

Medical countermeasures (MCMs) are products such as biologics and pharmaceutical drugs that can protect from or treat the health effects of a chemical, biological, radiological, or nuclear (CBRN) attack. MCMs can also be used for prevention and diagnosis of symptoms associated with CBRN attacks or threats. The FDA runs a program called the "FDA Medical Countermeasures Initiative" (MCMi), with programs funded by the federal government. It helps support "partner" agencies and organisations prepare for public health emergencies that could require MCMs.

Medications

FDA Building 51 houses the Center for Drug Evaluation and Research.

The Center for Drug Evaluation and Research uses different requirements for the three main drug product types: new drugs, generic drugs, and over-the-counter drugs. A drug is considered "new" if it is made by a different manufacturer, uses different excipients or inactive ingredients, is used for a different purpose, or undergoes any substantial change. The most rigorous requirements apply to new molecular entities: drugs that are not based on existing medications.[33]

New medications

New drugs receive extensive scrutiny before FDA approval in a process called a new drug application (NDA). Under the Trump administration, the agency has worked to make the drug-approval process go faster. Critics, however, argue that the FDA standards are not sufficiently rigorous, allowing unsafe or ineffective drugs to be approved. New drugs are available only by prescription by default. A change to over-the-counter (OTC) status is a separate process, and the drug must be approved through an NDA first. A drug that is approved is said to be "safe and effective when used as directed".

Very rare, limited exceptions to this multi-step process involving animal testing and controlled clinical trials can be granted out of compassionate use protocols. This was the case during the 2015 Ebola epidemic with the use, by prescription and authorization, of ZMapp and other experimental treatments, and for new drugs that can be used to treat debilitating and/or very rare conditions for which no existing remedies or drugs are satisfactory, or where there has not been an advance in a long period of time. The studies are progressively longer, gradually adding more individuals as they progress from stage I to stage III, normally over a period of years, and normally involve drug companies, the government and its laboratories, and often medical schools and hospitals and clinics. However, any exceptions to the aforementioned process are subject to strict review and scrutiny and conditions, and are only given if a substantial amount of research and at least some preliminary human testing has shown that they are believed to be somewhat safe and possibly effective. (See FDA Special Protocol Assessment about Phase III trials.)

Advertising and promotion

The FDA's Office of Prescription Drug Promotion reviews and regulates prescription drug advertising and promotion through surveillance activities and issuance of enforcement letters to pharmaceutical manufacturers. Advertising and promotion for over-the-counter drugs is regulated by the Federal Trade Commission. The FDA also empowers third-party enforcer-firms to engage in some regulatory oversight, e.g. the FDA expects pharmaceutical companies to make sure that third-party suppliers and labs abide by the agency's health and safety guidelines.

The drug advertising regulation contains two broad requirements: (1) a company may advertise or promote a drug only for the specific indication or medical use for which it was approved by FDA. Also, an advertisement must contain a "fair balance" between the benefits and the risks (side effects) of a drug.

The term off-label refers to the practice of prescribing a drug for a different purpose than what the FDA approved.

Post-market safety surveillance

After NDA approval, the sponsor must then review and report to the FDA every single patient adverse drug experience it learns of. They must report unexpected serious and fatal adverse drug events within 15 days, and other events on a quarterly basis. The FDA also receives directly adverse drug event reports through its MedWatch program. These reports are called "spontaneous reports" because reporting by consumers and health professionals is voluntary.

While this remains the primary tool of post-market safety surveillance, FDA requirements for post-marketing risk management are increasing. As a condition of approval, a sponsor may be required to conduct additional clinical trials, called Phase IV trials. In some cases, the FDA requires risk management plans called Risk Evaluation and Mitigation Strategies (REMS) for some drugs that require actions to be taken to ensure that the drug is used safely. For example, thalidomide can cause birth defects, but has uses that outweigh the risks if men and women taking the drugs do not conceive a child; a REMS program for thalidomide mandates an auditable process to ensure that people taking the drug take action to avoid pregnancy; many opioid drugs have REMS programs to avoid addiction and diversion of drugs. The drug isotretinoin has a REMS program called iPLEDGE.

Generic drugs

Generic drugs are chemical and therapeutic equivalents of name-brand drugs, normally whose patents have expired. Approved generic drugs should have the same dosage, safety, effectiveness, strength, stability, and quality, as well as route of administration. In general, they are less expensive than their name brand counterparts, are manufactured and marketed by rival companies and, in the 1990s, accounted for about a third of all prescriptions written in the United States. For a pharmaceutical company to gain approval to produce a generic drug, the FDA requires scientific evidence that the generic drug is interchangeable with or therapeutically equivalent to the originally approved drug. This is called an Abbreviated New Drug Application (ANDA). As of 2012, 80% of all FDA approved drugs are available in generic form.

Generic drug scandal

In 1989, a major scandal erupted involving the procedures used by the FDA to approve generic drugs for sale to the public. Charges of corruption in generic drug approval first emerged in 1988 during the course of an extensive congressional investigation into the FDA. The oversight subcommittee of the United States House Energy and Commerce Committee resulted from a complaint brought against the FDA by Mylan Laboratories Inc. of Pittsburgh. When its application to manufacture generics were subjected to repeated delays by the FDA, Mylan, convinced that it was being discriminated against, soon began its own private investigation of the agency in 1987. Mylan eventually filed suit against two former FDA employees and four drug-manufacturing companies, charging that corruption within the federal agency resulted in racketeering and in violations of antitrust law. "The order in which new generic drugs were approved was set by the FDA employees even before drug manufacturers submitted applications" and, according to Mylan, this illegal procedure was followed to give preferential treatment to certain companies. During the summer of 1989, three FDA officials (Charles Y. Chang, David J. Brancato, Walter Kletch) pleaded guilty to criminal charges of accepting bribes from generic drugs makers, and two companies (Par Pharmaceutical and its subsidiary Quad Pharmaceuticals) pleaded guilty to giving bribes.

Furthermore, it was discovered that several manufacturers had falsified data submitted in seeking FDA authorization to market certain generic drugs. Vitarine Pharmaceuticals of New York, which sought approval of a generic version of the drug Dyazide, a medication for high blood pressure, submitted Dyazide, rather than its generic version, for the FDA tests. In April 1989, the FDA investigated 11 manufacturers for irregularities; and later brought that number up to 13. Dozens of drugs were eventually suspended or recalled by manufacturers. In the early 1990s, the U.S. Securities and Exchange Commission filed securities fraud charges against the Bolar Pharmaceutical Company, a major generic manufacturer based in Long Island, New York.

Over-the-counter drugs

Over-the-counter (OTC) are drugs like aspirin that do not require a doctor's prescription. The FDA has a list of approximately 800 such approved ingredients that are combined in various ways to create more than 100,000 OTC drug products. Many OTC drug ingredients had been previously approved prescription drugs now deemed safe enough for use without a medical practitioner's supervision like ibuprofen.

Ebola treatment

In 2014, the FDA added an Ebola treatment being developed by Canadian pharmaceutical company Tekmira to the Fast Track program, but halted the phase 1 trials in July pending the receipt of more information about how the drug works. This was widely viewed as increasingly important in the face of a major outbreak of the disease in West Africa that began in late March 2014 and ended in June 2016.

Coronavirus (COVID-19) testing

During the coronavirus pandemic, FDA granted emergency use authorization for personal protective equipment (PPE), in vitro diagnostic equipment, ventilators and other medical devices.

On March 18, 2020, FDA inspectors postponed most foreign facility inspections and all domestic routine surveillance facility inspections. In contrast, the USDA's Food Safety and Inspection Service (FSIS) continued inspections of meatpacking plants, which resulted in 145 FSIS field employees who tested positive for COVID-19, and three who died.

Vaccines, blood and tissue products, and biotechnology

FDA scientist prepares blood donation samples for testing.

The Center for Biologics Evaluation and Research is the branch of the FDA responsible for ensuring the safety and efficacy of biological therapeutic agents. These include blood and blood products, vaccines, allergenics, cell and tissue-based products, and gene therapy products. New biologics are required to go through a premarket approval process called a Biologics License Application (BLA), similar to that for drugs.

The original authority for government regulation of biological products was established by the 1902 Biologics Control Act, with additional authority established by the 1944 Public Health Service Act. Along with these Acts, the Federal Food, Drug, and Cosmetic Act applies to all biologic products, as well. Originally, the entity responsible for regulation of biological products resided under the National Institutes of Health; this authority was transferred to the FDA in 1972.

Medical and radiation-emitting devices

FDA Building 62 houses the Center for Devices and Radiological Health.

The Center for Devices and Radiological Health (CDRH) is the branch of the FDA responsible for the premarket approval of all medical devices, as well as overseeing the manufacturing, performance and safety of these devices. The definition of a medical device is given in the FD&C Act, and it includes products from the simple toothbrush to complex devices such as implantable neurostimulators. CDRH also oversees the safety performance of non-medical devices that emit certain types of electromagnetic radiation. Examples of CDRH-regulated devices include cellular phones, airport baggage screening equipment, television receivers, microwave ovens, tanning booths, and laser products.

CDRH regulatory powers include the authority to require certain technical reports from the manufacturers or importers of regulated products, to require that radiation-emitting products meet mandatory safety performance standards, to declare regulated products defective, and to order the recall of defective or noncompliant products. CDRH also conducts limited amounts of direct product testing.

"FDA-Cleared" vs "FDA-Approved"

Clearance requests are required for medical devices that prove they are "substantially equivalent" to the predicate devices already on the market. Approved requests are for items that are new or substantially different and need to demonstrate "safety and efficacy", for example they may be inspected for safety in case of new toxic hazards. Both aspects need to be proved or provided by the submitter to ensure proper procedures are followed.

Cosmetics

Cosmetics are regulated by the Center for Food Safety and Applied Nutrition, the same branch of the FDA that regulates food. Cosmetic products are not, in general, subject to premarket approval by the FDA unless they make "structure or function claims" that make them into drugs (see Cosmeceutical). However, all color additives must be specifically FDA approved before manufacturers can include them in cosmetic products sold in the U.S. The FDA regulates cosmetics labeling, and cosmetics that have not been safety tested must bear a warning to that effect.

According to the industry advocacy group the American Council on Science and Health, though the cosmetic industry is predominantly responsible in ensuring the safety of its products, the FDA also has the power to intervene when necessary to protect the public but in general does not require pre-market approval or testing. The ACSH says that companies are required to place a warning note on their products if they have not been tested and that experts in cosmetic ingredient reviews also play a role in monitoring safety through influence on the use of ingredients, but also lack legal authority. According to the ACSH, overall the organization has reviewed about 1,200 ingredients and has suggested that several hundred be restricted, but there is no standard or systemic method for reviewing chemicals for safety and a clear definition of what is meant by 'safety' so that all chemicals are tested on the same basis.

Veterinary products

The Center for Veterinary Medicine (CVM) is a center of the FDA that regulates food additives and drugs that are given to animals. CVM regulates animal drugs, animal food including pet animal, and animal medical devices. The FDA's requirements to prevent the spread of bovine spongiform encephalopathy are also administered by CVM through inspections of feed manufacturers. CVM does not regulate vaccines for animals; these are handled by the United States Department of Agriculture.

Tobacco products

The FDA regulates tobacco products with authority established by the 2009 Family Smoking Prevention and Tobacco Control Act. This Act requires color warnings on cigarette packages and printed advertising, and text warnings from the U.S. Surgeon General.[66]

The nine new graphic warning labels were announced by the FDA in June 2011 and were scheduled to be required to appear on packaging by September 2012. The implementation date is uncertain, due to ongoing proceedings in the case of R.J. Reynolds Tobacco Co. v. U.S. Food and Drug Administration. R.J. Reynolds, Lorillard, Commonwealth Brands, Liggett Group and Santa Fe Natural Tobacco Company have filed suit in Washington, D.C. federal court claiming that the graphic labels are an unconstitutional way of forcing tobacco companies to engage in anti-smoking advocacy on the government's behalf.

A First Amendment lawyer, Floyd Abrams, is representing the tobacco companies in the case, contending requiring graphic warning labels on a lawful product cannot withstand constitutional scrutiny. The Association of National Advertisers and the American Advertising Federation have also filed a brief in the suit, arguing that the labels infringe on commercial free speech and could lead to further government intrusion if left unchallenged. In November 2011, Federal judge Richard Leon of the U.S. District Court for the District of Columbia temporarily halted the new labels, likely delaying the requirement that tobacco companies display the labels. The U.S. Supreme Court ultimately could decide the matter.

In July 2017, the FDA announced a plan that would reduce the current levels of nicotine permitted in tobacco cigarettes.

Regulation of living organisms

With acceptance of premarket notification 510(k) k033391 in January 2004, the FDA granted Ronald Sherman permission to produce and market medical maggots for use in humans or other animals as a prescription medical device. Medical maggots represent the first living organism allowed by the Food and Drug Administration for production and marketing as a prescription medical device.

In June 2004, the FDA cleared Hirudo medicinalis (medicinal leeches) as the second living organism legal to use as a medical device.

The FDA also requires that milk be pasteurized to remove bacteria.

International Cooperation

In February 2011, President Barack Obama and Canadian Prime Minister Stephen Harper issued a "Declaration on a Shared Vision for Perimeter Security and Economic Competitiveness" and announced the creation of the Canada-United States Regulatory Cooperation Council (RCC) "to increase regulatory transparency and coordination between the two countries."

Under the RCC mandate, the FDA and Health Canada undertook a "first of its kind" initiative by selecting "as its first area of alignment common cold indications for certain over-the-counter antihistamine ingredients (GC 2013-01-10)."

A more recent example of the FDA's international work is their 2018 cooperation with regulatory and law-enforcement agencies worldwide through Interpol as part of Operation Pangea XI. The FDA targeted 465 websites that illegally sold potentially dangerous, unapproved versions of opioid, oncology, and antiviral prescription drugs to U.S. consumers. The agency focused on transaction laundering schemes in order to uncover the complex online drug network.

Science and research programs

FDA lab at Building 64 in Silver Spring, Maryland

The FDA carries out research and development activities to develop technology and standards that support its regulatory role, with the objective of resolving scientific and technical challenges before they become impediments. The FDA's research efforts include the areas of biologics, medical devices, drugs, women's health, toxicology, food safety and applied nutrition, and veterinary medicine.

Data management

The FDA has collected a large amount of data through the decades. The OpenFDA project was created to enable easy access of the data for the public and was officially launched in June 2014.[86][87]

History

Up until the 20th century, there were few federal laws regulating the contents and sale of domestically produced food and pharmaceuticals, with one exception being the short-lived Vaccine Act of 1813. The history of the FDA can be traced to the latter part of the 19th century and the Division of Chemistry of the U.S. Department of Agriculture, which itself derived from the Copyright and Patent Clause. Under Harvey Washington Wiley, appointed chief chemist in 1883, the Division began conducting research into the adulteration and misbranding of food and drugs on the American market. Wiley's advocacy came at a time when the public had become aroused to hazards in the marketplace by muckraking journalists like Upton Sinclair, and became part of a general trend for increased federal regulations in matters pertinent to public safety during the Progressive Era. The Biologics Control Act of 1902 was put in place after a diphtheria antitoxin derived from tetanus-contaminated serum caused the deaths of thirteen children in St. Louis, Missouri. The serum was originally collected from a horse named Jim who had contracted tetanus.

Harvey W. Wiley, chief advocate of the Food and Drug Act

In June 1906, President Theodore Roosevelt signed into law the Pure Food and Drug Act of 1906, also known as the "Wiley Act" after its chief advocate. The Act prohibited, under penalty of seizure of goods, the interstate transport of food that had been "adulterated". The Act applied similar penalties to the interstate marketing of "adulterated" drugs, in which the "standard of strength, quality, or purity" of the active ingredient was not either stated clearly on the label or listed in the United States Pharmacopeia or the National Formulary.

The responsibility for examining food and drugs for such "adulteration" or "misbranding" was given to Wiley's USDA Bureau of Chemistry. Wiley used these new regulatory powers to pursue an aggressive campaign against the manufacturers of foods with chemical additives, but the Chemistry Bureau's authority was soon checked by judicial decisions, which narrowly defined the bureau's powers and set high standards for proof of fraudulent intent. In 1927, the Bureau of Chemistry's regulatory powers were reorganized under a new USDA body, the Food, Drug, and Insecticide Administration. This name was shortened to the Food and Drug Administration (FDA) three years later.

By the 1930s, muckraking journalists, consumer protection organizations, and federal regulators began mounting a campaign for stronger regulatory authority by publicizing a list of injurious products that had been ruled permissible under the 1906 law, including radioactive beverages, mascara that could cause blindness, and worthless "cures" for diabetes and tuberculosis. The resulting proposed law did not get through the Congress of the United States for five years, but was rapidly enacted into law following the public outcry over the 1937 Elixir Sulfanilamide tragedy, in which over 100 people died after using a drug formulated with a toxic, untested solvent.

President Franklin Delano Roosevelt signed the Federal Food, Drug, and Cosmetic Act into law on June 24, 1938. The new law significantly increased federal regulatory authority over drugs by mandating a pre-market review of the safety of all new drugs, as well as banning false therapeutic claims in drug labeling without requiring that the FDA prove fraudulent intent.

Soon after passage of the 1938 Act, the FDA began to designate certain drugs as safe for use only under the supervision of a medical professional, and the category of "prescription-only" drugs was securely codified into law by the Durham-Humphrey Amendment in 1951. These developments confirmed extensive powers for the FDA to enforce post-marketing recalls of ineffective drugs.

Medical Officer Alexander Fleming, M. D., examines a portion of a 240-volume new drug application around the late 1980s. Applications grew considerably after the efficacy mandate under the 1962 Drug Amendments.

Outside of the US, the drug thalidomide was marketed for the relief of general nausea and morning sickness, but caused birth defects and even the death of thousands of babies when taken during pregnancy. American mothers were largely unaffected as Frances Oldham Kelsey of the FDA refused to authorize the medication for market. In 1962, the Kefauver-Harris Amendment to the FD&C Act was passed, which represented a "revolution" in FDA regulatory authority. The most important change was the requirement that all new drug applications demonstrate "substantial evidence" of the drug's efficacy for a marketed indication, in addition to the existing requirement for pre-marketing demonstration of safety. This marked the start of the FDA approval process in its modern form.

These reforms had the effect of increasing the time, and the difficulty, required to bring a drug to market. One of the most important statutes in establishing the modern American pharmaceutical market was the 1984 Drug Price Competition and Patent Term Restoration Act, more commonly known as the "Hatch-Waxman Act" after its chief sponsors. The act extended the patent exclusivity terms of new drugs, and tied those extensions, in part, to the length of the FDA approval process for each individual drug. For generic manufacturers, the Act created a new approval mechanism, the Abbreviated New Drug Application (ANDA), in which the generic drug manufacturer need only demonstrate that their generic formulation has the same active ingredient, route of administration, dosage form, strength, and pharmacokinetic properties ("bioequivalence") as the corresponding brand-name drug. This Act has been credited with, in essence, creating the modern generic drug industry.

Concerns about the length of the drug approval process were brought to the fore early in the AIDS epidemic. In the mid- and late 1980s, ACT-UP and other HIV activist organizations accused the FDA of unnecessarily delaying the approval of medications to fight HIV and opportunistic infections. Partly in response to these criticisms, the FDA issued new rules to expedite approval of drugs for life-threatening diseases, and expanded pre-approval access to drugs for patients with limited treatment options. All of the initial drugs approved for the treatment of HIV/AIDS were approved through these accelerated approval mechanisms. Frank Young, then commissioner of the FDA, was behind the Action Plan Phase II, established in August 1987 for quicker approval of AIDS medication.

In two instances, state governments have sought to legalize drugs that the FDA has not approved. Under the theory that federal law, passed pursuant to Constitutional authority, overrules conflicting state laws, federal authorities still claim the authority to seize, arrest, and prosecute for possession and sales of these substances, even in states where they are legal under state law. The first wave was the legalization by 27 states of laetrile in the late 1970s. This drug was used as a treatment for cancer, but scientific studies both before and after this legislative trend found it ineffective. The second wave concerned medical marijuana in the 1990s and 2000s. Though Virginia passed legislation allowing doctors to recommend cannabis for glaucoma or the side effects of chemotherapy, a more widespread trend began in California with the Compassionate Use Act of 1996.

When the FDA requested Endo Pharmaceuticals on June 8, 2017, to remove oxymorphone hydrochloride from the market, it was the first such request in FDA history.

21st century reforms

Critical Path Initiative

The Critical Path Initiative is the FDA's effort to stimulate and facilitate a national effort to modernize the sciences through which FDA-regulated products are developed, evaluated, and manufactured. The Initiative was launched in March 2004, with the release of a report entitled Innovation/Stagnation: Challenge and Opportunity on the Critical Path to New Medical Products.

Patients' rights to access unapproved drugs

The Compassionate Investigational New Drug program was created after Randall v. U.S. ruled in favor of Robert C. Randall in 1978, creating a program for medical marijuana.

A 2006 court case, Abigail Alliance v. von Eschenbach, would have forced radical changes in FDA regulation of unapproved drugs. The Abigail Alliance argued that the FDA must license drugs for use by terminally ill patients with "desperate diagnoses," after they have completed Phase I testing. The case won an initial appeal in May 2006, but that decision was reversed by a March 2007 rehearing. The US Supreme Court declined to hear the case, and the final decision denied the existence of a right to unapproved medications.

Critics of the FDA's regulatory power argue that the FDA takes too long to approve drugs that might ease pain and human suffering faster if brought to market sooner. The AIDS crisis created some political efforts to streamline the approval process. However, these limited reforms were targeted for AIDS drugs, not for the broader market. This has led to the call for more robust and enduring reforms that would allow patients, under the care of their doctors, access to drugs that have passed the first round of clinical trials.

Post-marketing drug safety monitoring

The widely publicized recall of Vioxx, a non-steroidal anti-inflammatory drug (NSAID) now estimated to have contributed to fatal heart attacks in thousands of Americans, played a strong role in driving a new wave of safety reforms at both the FDA rulemaking and statutory levels. The FDA approved Vioxx in 1999, and initially hoped it would be safer than previous NSAIDs due to its reduced risk of intestinal tract bleeding. However, a number of pre and post-marketing studies suggested that Vioxx might increase the risk of myocardial infarction, and results from the APPROVe trial in 2004 conclusively demonstrated this.

Faced with numerous lawsuits, the manufacturer voluntarily withdrew it from the market. The example of Vioxx has been prominent in an ongoing debate over whether new drugs should be evaluated on the basis of their absolute safety, or their safety relative to existing treatments for a given condition. In the wake of the Vioxx recall, there were widespread calls by major newspapers, medical journals, consumer advocacy organizations, lawmakers, and FDA officials for reforms in the FDA's procedures for pre- and post-market drug safety regulation.

In 2006, a Congressional committee was appointed by the Institute of Medicine to review pharmaceutical safety regulation in the U.S. and to issue recommendations for improvements. The committee was composed of 16 experts, including leaders in clinical medicine medical research, economics, biostatistics, law, public policy, public health, and the allied health professions, as well as current and former executives from the pharmaceutical, hospital, and health insurance industries. The authors found major deficiencies in the current FDA system for ensuring the safety of drugs on the American market. Overall, the authors called for an increase in the regulatory powers, funding, and independence of the FDA. Some of the committee's recommendations were incorporated into drafts of the PDUFA IV amendment, which was signed into law as the Food and Drug Administration Amendments Act of 2007.

As of 2011, Risk Minimization Action Plans (RiskMAPS) have been created to ensure risks of a drug never outweigh the benefits of that drug within the post-marketing period. This program requires that manufacturers design and implement periodic assessments of their programs' effectiveness. The Risk Minimization Action Plans are set in place depending on the overall level of risk a prescription drug is likely to pose to the public.

Pediatric drug testing

Prior to the 1990s, only 20% of all drugs prescribed for children in the United States were tested for safety or efficacy in a pediatric population. This became a major concern of pediatricians as evidence accumulated that the physiological response of children to many drugs differed significantly from those drugs' effects on adults. Children react differently to the drugs because of many reasons, including size, weight, etc. There were several reasons that few medical trials were done with children. For many drugs, children represented such a small proportion of the potential market, that drug manufacturers did not see such testing as cost-effective.

Also, the belief that children are ethically restricted in their ability to give informed consent brought increased governmental and institutional hurdles to approval of these clinical trials, and greater concerns about legal liability. Thus, for decades, most medicines prescribed to children in the U.S. were done so in a non-FDA-approved, "off-label" manner, with dosages "extrapolated" from adult data through body weight and body-surface-area calculations.

In an initial FDA attempt to address this issue they produced the 1994 FDA Final Rule on Pediatric Labeling and Extrapolation, which allowed manufacturers to add pediatric labeling information, but required drugs that had not been tested for pediatric safety and efficacy to bear a disclaimer to that effect. However, this rule failed to motivate many drug companies to conduct additional pediatric drug trials. In 1997, the FDA proposed a rule to require pediatric drug trials from the sponsors of New Drug Applications. However, this new rule was successfully preempted in federal court as exceeding the FDA's statutory authority.

While this debate was unfolding, Congress used the Food and Drug Administration Modernization Act of 1997 to pass incentives that gave pharmaceutical manufacturers a six-month patent term extension on new drugs submitted with pediatric trial data. The Best Pharmaceuticals for Children Act of 2007 reauthorized these provisions and allowed the FDA to request NIH-sponsored testing for pediatric drug testing, although these requests are subject to NIH funding constraints. In the Pediatric Research Equity Act of 2003, Congress codified the FDA's authority to mandate manufacturer-sponsored pediatric drug trials for certain drugs as a "last resort" if incentives and publicly funded mechanisms proved inadequate.

Priority review voucher (PRV)

The priority review voucher is a provision of the Food and Drug Administration Amendments Act of 2007, which awards a transferable "priority review voucher" to any company that obtains approval for a treatment for a neglected tropical diseases. The system was first proposed by Duke University faculty David Ridley, Henry Grabowski, and Jeffrey Moe in their 2006 Health Affairs paper: "Developing Drugs for Developing Countries". President Obama signed into law the Food and Drug Administration Safety and Innovation Act of 2012, which extended the authorization until 2017.

Rules for generic biologics

Since the 1990s, many successful new drugs for the treatment of cancer, autoimmune diseases, and other conditions have been protein-based biotechnology drugs, regulated by the Center for Biologics Evaluation and Research. Many of these drugs are extremely expensive; for example, the anti-cancer drug Avastin costs $55,000 for a year of treatment, while the enzyme replacement therapy drug Cerezyme costs $200,000 per year, and must be taken by Gaucher's disease patients for life.

Biotechnology drugs do not have the simple, readily verifiable chemical structures of conventional drugs, and are produced through complex, often proprietary, techniques, such as transgenic mammalian cell cultures. Because of these complexities, the 1984 Hatch-Waxman Act did not include biologics in the Abbreviated New Drug Application (ANDA) process. This precluded the possibility of generic drug competition for biotechnology drugs. In February 2007, identical bills were introduced into the House to create an ANDA process for the approval of generic biologics, but were not passed.

Mobile medical applications

In 2013, a guidance was issued to regulate mobile medical applications and protect users from their unintended use. This guidance distinguishes the apps subjected to regulation based on the marketing claims of the apps. Incorporation of the guidelines during the development phase of these apps has been proposed for expedited market entry and clearance.

Criticism

The FDA has regulatory oversight over a large array of products that affect the health and life of American citizens. As a result, the FDA's powers and decisions are carefully monitored by several governmental and non-governmental organizations. A $1.8 million 2006 Institute of Medicine report on pharmaceutical regulation in the U.S. found major deficiencies in the current FDA system for ensuring the safety of drugs on the American market. Overall, the authors called for an increase in the regulatory powers, funding, and independence of the FDA.

A 2022 article from Politico raised concerns that food is not a high priority at the FDA. The report explains the FDA has structural and leadership problems in the food division and is often deferential to industry. This might be attributed to lobbying and influence of big food companies in Washington, D.C.

During the COVID-19 pandemic, the FDA received criticism for punishing small distilleries that made hand sanitizers to help meet the unexpected demand. After receiving $14,000 fines from the FDA, some producers stated, "I wish we'd never done it. I will not put myself on this same chopping block again."

E-patient

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