Cancer

Cancer, known medically as a malignant neoplasm, is a broad group of various diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also metastasize to more distant parts of the body through the lymphatic system or bloodstream. Not all tumors are cancerous. Benign tumors do not grow uncontrollably, do not invade neighboring tissues, and do not spread throughout the body. There are over 200 different known cancers that afflict humans.
Determining what causes cancer is complex. Many things are known to increase the risk of cancer, including tobacco use, certain infections, radiation, lack of physical activity, obesity, and environmental pollutants. Approximately 5-10% of cancers are entirely hereditary.
Cancer can be detected in a number of ways, including the presence of certain symptoms, screening tests, or medical imaging. Once a possible cancer is detected it's diagnosed by microscopic examination of a biopsy sample. Cancer is usually treated with chemotherapy, radiation therapy, and surgery. The chances of surviving the disease vary greatly by the type and location of the cancer and the extent of disease at the start of treatment. While cancer can affect people of all ages, and a few types of cancer are more common in children, the risk of developing cancer generally increases with age. In 2007, cancer caused about 13% of all human deaths worldwide (7.9 million). Rates are rising as more people live to an old age and as mass lifestyle changes occur in the developing world.
The medical speciality dealing with the diagnosis, treatment and study of cancer is oncology.
==Signs and symptoms==
When cancer begins it invariably produces no symptoms with signs and symptoms only appearing as the mass continues to grow or ulcerates. Few symptoms are unique to cancer, with many cancer symptoms also frequently occurring in individuals who have other conditions. Thus it's not uncommon for people diagnosed with cancer to have been treated for other diseases to which it was assumed their symptoms were due.
===Local effects===
Local symptoms may occur due to the mass of the tumor or its ulceration. For example mass effects from lung cancer can cause blockage of the bronchus resulting in cough or pneumonia. Esophageal cancer can cause narrowing of the oesophagus making it difficult or painful to swallow, and colorectal cancer may lead to narrowing or blockages in the bowel resulting in changes in bowel habits. Masses in the breast or testicles may often be easily felt. Ulceration can cause bleeding which, if it occurs in the lung, will lead to coughing up blood, in the bowels to anemia or rectal bleeding, in the bladder to blood in the urine, and in the uterus to vaginal bleeding. Although localized pain may occur in advanced cancer, the initial swelling is usually painless. Some cancers can cause build up of fluid within the chest or abdomen.
===Systemic symptoms===
General symptoms occur due to distant effects of the cancer that are not related to direct or metastatic spread. These may include: unintentional weight loss, fever, being excessively tired, and changes to the skin. Hodgkin's lymphoma, leukemia, and cancers of the liver or kidney can cause a persistent fever of unknown origin.
Specific constellations of systemic symptoms, termed paraneoplastic phenomena, may occur with some cancers. Examples include the appearance of myasthenia gravis in thymoma (See Jeff Forrester in Spin) and clubbing in lung cancer (see George in Que Será Será).
===Metastasis===
Symptoms of metastasis are due to the spread of cancer to other locations in the body. They can include enlarged lymph nodes (which can be felt or sometimes seen under the skin and are typically hard), enlarged liver or enlarged spleen which can be felt in the abdomen, pain or fracture of affected bones, and neurological symptoms.
==Causes==
Cancers are primarily an environmental disease with 90-95% of cases attributed to environmental factors and 5-10% due to genetics. Environmental, as used by cancer researchers, means any cause that is not inherited genetically, not merely pollution but also substances and conditions at home and at the workplace, including diet, smoking, alcohol, drugs, exposure to chemicals, sunlight, ionizing radiation, electromagnetic fields, infectious agents, etc.. Lifestyle, economic, and behavioral factors are all aspects of environmental causes. Common environmental factors that contribute to cancer death include tobacco (25-30%), diet and obesity (30-35%), infections (15-20%), radiation (both ionizing and non-ionizing, up to 10%), stress, lack of physical activity, and environmental pollutants.
It's nearly impossible to prove what caused a cancer in any individual, because most cancers have multiple possible causes. For example, if a person who uses tobacco heavily develops lung cancer, then it was probably caused by the tobacco use, but since everyone has a small chance of developing lung cancer as a result of air pollution or radiation, then there's a small chance that the cancer developed because of air pollution or radiation.
===Chemicals===
Cancer pathogenesis is traceable back to DNA mutations that impact cell growth and metastasis. Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens. Particular substances have been linked to specific types of cancer. Tobacco smoking is associated with many forms of cancer and causes 90% of lung cancer.
Many mutagens are also carcinogens, but some carcinogens are not mutagens. Alcohol is an example of a chemical carcinogen that's not a mutagen. In Western Europe 10% of cancers in males and 3% of cancers in females are attributed to alcohol.
Decades of research has demonstrated the link between tobacco use and cancer in the lung, larynx, head, neck, stomach, bladder, kidney, esophagus, and pancreas. Tobacco smoke contains over fifty known carcinogens, including nitrosamines and polycyclic aromatic hydrocarbons. Tobacco is responsible for about one in three of all cancer deaths in the developed world, and about one in five worldwide. Lung cancer death rates in the United States have mirrored tobacco smoking patterns, with increases in smoking followed by dramatic increases in lung cancer death rates and, more recently, decreases in smoking rates since the 1950s followed by decreases in lung cancer death rates in men since 1990. However, the numbers of smokers worldwide is still rising, leading to what some organizations have described as the tobacco epidemic.
Cancer related to one's occupation is believed to represent between 2–20% of all cases. Every year, at least 200,000 people die worldwide from cancer related to their workplace. Most cancer deaths caused by occupational risk factors occur in the developed world. It's estimated that approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the U.S. are attributable to occupation. Millions of workers run the risk of developing cancers such as lung cancer and mesothelioma from inhaling asbestos fibers and tobacco smoke, or leukemia from exposure to benzene at their workplaces.
===Diet and exercise===
Diet, physical inactivity, and obesity are related to approximately 30–35% of cancer deaths. In the United States excess body weight is associated with the development of many types of cancer and is a factor in 14–20% of all cancer deaths. Physical inactivity is believed to contribute to cancer risk not only through its effect on body weight but also through negative effects on the immune system and the endocrine system.
Diets that are low in vegetables, fruits and whole grains, and high in processed or red meats are linked with a number of cancers. A high salt diet is linked to gastric cancer, aflatoxin B1, a frequent food contaminate, with liver cancer, and Betel nut chewing with oral cancer. This may partly explain differences in cancer incidence in different countries. For example gastric cancer is more common in Japan with its high salt diet and colon cancer is more common in the United States. Immigrants develop the risk of their new country, often within one generation, suggesting a substantial link between diet and cancer.
===Infection===
Worldwide approximately 18% of cancer deaths are related to infectious diseases. This proportion varies in different regions of the world from a high of 25% in Africa to less than 10% in the developed world. Viruses are the usual infectious agents that cause cancer but bacteria and parasites may also have an effect.
A virus that can cause cancer is called an oncovirus. These include human papillomavirus (cervical carcinoma), Epstein-Barr virus (B cell lymphoproliferative disease and nasopharynx cancer), Kaposi's sarcoma herpesvirus (Kaposi's Sarcoma and primary effusion lymphomas), hepatitis B and hepatitis C viruses (hepatocellular carcinoma), and Human T-lymphotropic virus 1 (T-cell leukemias). Bacterial infection may also increase the risk of cancer, as seen in Helicobacter pylori-induced gastric carcinoma. Parasitic infections strongly associated with cancer include Schistosoma haematobium (squamous cell carcinoma of the bladder) and the liver flukes, Opisthorchis viverrini and Clonorchis sinensis (cholangiocarcinoma).
===Radiation===
Up to 10% of invasive cancers are related to radiation exposure, including both ionizing radiation and non-ionizing radiation. Additionally, the vast majority of non-invasive cancers are non-melanoma skin cancers caused by non-ionizing ultraviolet radiation.
Sources of ionizing radiation include medical imaging, and radon gas. Radiation can cause cancer in most parts of the body, in all animals, and at any age, although radiation-induced solid tumors usually take 10-15 years, and can take up to 40 years, to become clinically manifest, and radiation-induced leukemias typically require 2-10 years to appear. Some people, such as those with nevoid basal cell carcinoma syndrome or retinoblastoma, are more susceptible than average to developing cancer from radiation exposure. Children and adolescents are twice as likely to develop radiation-induced leukemia as adults; radiation exposure before birth has ten times the effect. Ionizing radiation is not a particularly strong mutagen. Residential exposure to radon gas, for example, has similar cancer risks as passive smoking. Low-dose exposures, such as living near a nuclear power plant, are generally believed to have no or very little effect on cancer development. Radiation is a more potent source of cancer when it's combined with other cancer-causing agents, such as radon gas exposure plus smoking tobacco.
Unlike chemical or physical triggers for cancer, ionizing radiation hits molecules within cells randomly. If it happens to strike a chromosome, it can break the chromosome, result in an abnormal number of chromosomes, inactivate one or more genes in the part of the chromosome that it hit, delete parts of the DNA sequence, cause chromosome translocations, or cause other types of chromosome abnormalities. Major damage normally results in the cell dying, but smaller damage may leave a stable, partly functional cell that may be capable of proliferating and developing into cancer, especially if tumor suppressor genes were damaged by the radiation. Three independent stages appear to be involved in the creation of cancer with ionizing radiation: morphological changes to the cell, acquiring cellular immortality (losing normal, life-limiting cell regulatory processes), and adaptations that favor formation of a tumor. Even if the radiation particle does not strike the DNA directly, it triggers responses from cells that indirectly increase the likelihood of mutations.
Medical use of ionizing radiation is a growing source of radiation-induced cancers. Ionizing radiation may be used to treat other cancers, but this may, in some cases, induce a second form of cancer. It's also used in some kinds of medical imaging. One report estimates that approximately 29,000 future cancers could be related to the approximately 70 million CT scans performed in the US in 2007. It's estimated that 0.4% of cancers in 2007 in the United States are due to CTs performed in the past and that this may increase to as high as 1.5–2% with rates of CT usage during this same time period.
Prolonged exposure to ultraviolet radiation from the sun can lead to melanoma and other skin malignancies. Clear evidence establishes ultraviolet radiation, especially the non-ionizing medium wave UVB, as the cause of most non-melanoma skin cancers, which are the most common forms of cancer in the world.
Non-ionizing radio frequency radiation from mobile phones, electric power transmission, and other similar sources have been described as a possible carcinogen by the World Health Organization's International Agency for Research on Cancer.
===Heredity===
The vast majority of cancers are non-hereditary ("sporadic cancers"). Hereditary cancers are primarily caused by an inherited genetic defect. Less than 0.3% of the population are carriers of a genetic mutation which has a large effect on cancer risk and these cause less than 3–10% of all cancer. Some of these syndromes include: certain inherited mutations in the genes BRCA1 and BRCA2 with a more than 75% risk of breast cancer and ovarian cancer, and hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome) which is present in about 3% of people with colorectal cancer, among others.
===Physical agents===
Some substances cause cancer primarily through their physical, rather than chemical, effects on cells.
A prominent example of this is prolonged exposure to asbestos, naturally occurring mineral fibers which are a major cause of mesothelioma, a type of lung cancer. Other substances in this category, including both naturally occurring and synthetic asbestos-like fibers such as wollastonite, attapulgite, glass wool, and rock wool, are believed to have similar effects.
Non-Fibrous particulate materials that cause cancer include powdered metallic cobalt and nickel, and crystalline silica (quartz, cristobalite, and tridymite).
Usually, physical carcinogens must get inside the body (such as through inhaling tiny pieces) and require years of exposure to develop cancer.
Physical trauma resulting in cancer is relatively rare. Claims that breaking bone resulted in bone cancer, for example, have never been proven. Similarly, physical trauma is not accepted as a cause for cervical cancer, breast cancer, or brain cancer.
One accepted source is frequent, long-term application of hot objects to the body. It's possible that repeated burns on the same part of the body, such as those produced by kanger and kairo heaters (charcoal hand warmers), may produce skin cancer, especially if carcinogenic chemicals are also present. Frequently drinking scalding hot tea may produce esophageal cancer.
Generally, it's believed that the cancer arises, or a pre-existing cancer is encouraged, during the process of repairing the trauma, rather than the cancer being caused directly by the trauma. However, repeated injuries to the same tissues might promote excessive cell proliferation, which could then increase the odds of a cancerous mutation. There's no evidence that inflammation itself causes cancer.
===Hormones===
Some hormones play a role in the development of cancer by promoting cell proliferation. Hormones are important agents in sex-related cancers such as cancer of the breast, endometrium, prostate, ovary, and testicles, and also of thyroid cancer and bone cancer.
An individual's hormone levels are mostly determined genetically, so this may at least partly explains the presence of some cancers that run in families that do not seem to have any cancer-causing genes. For example, the daughters of women who have breast cancer have significantly higher levels of estrogen and progesterone than the daughters of women without breast cancer. These higher hormone levels may explain why these women have higher risk of breast cancer, even in the absence of a breast-cancer gene. Similarly, men of African ancestry have significantly higher levels of testosterone than men of European ancestry, and have a correspondingly much higher level of prostate cancer. Men of Asian ancestry, with the lowest levels of testosterone-activating androstanediol glucuronide, have the lowest levels of prostate cancer.
However, non-genetic factors are also relevant: obese people have higher levels of some hormones associated with cancer and a higher rate of those cancers. Women who take hormone replacement therapy have a higher risk of developing cancers associated with those hormones. On the other hand, people who exercise far more than average have lower levels of these hormones, and lower risk of cancer. Osteosarcoma may be promoted by growth hormones. Some treatments and prevention approaches leverage this cause by artificially reducing hormone levels, and thus discouraging hormone-sensitive cancers.
===Other===
Excepting the rare transmissions that occur with pregnancies and only a marginal few organ donors, cancer is generally not a transmissible disease. The main reason for this is tissue graft rejection caused by major histocompatibility complex incompatibility. In humans and other vertebrates, the immune system uses MHC antigens to differentiate between "self" and "non-self" cells because these antigens are different from person to person. When non-self antigens are encountered, the immune system reacts against the appropriate cell. Such reactions may protect against tumour cell engraftment by eliminating implanted cells. In the United States, approximately 3,500 pregnant women have a malignancy annually, and transplacental transmission of acute leukemia, lymphoma, melanoma and carcinoma from mother to fetus has been observed. The development of donor-derived tumors from organ transplants is exceedingly rare (despite the events in Not Cancer). The main cause of organ transplant associated tumors seems to be malignant melanoma, that was undetected at the time of organ harvest. Cancer from one organism will usually grow in another organism of that species, as long as they share the same histocompatibility genes, proven using mice; however this would never happen in a real-world setting except as described above.
In non-humans, a few types of transmissible cancer have been described, wherein the cancer spreads between animals by transmission of the tumor cells themselves. This phenomenon is seen in dogs with Sticker's sarcoma, also known as canine transmissible venereal tumor, as well as devil facial tumour disease in Tasmanian devils.
==Pathophysiology==
Cancer is fundamentally a disease of failure of regulation of tissue growth. In order for a normal cell to transform into a cancer cell, the genes which regulate cell growth and differentiation must be altered.
The affected genes are divided into two broad categories. Oncogenes are genes which promote cell growth and reproduction. Tumor suppressor genes are genes which inhibit cell division and survival. Malignant transformation can occur through the formation of novel oncogenes, the inappropriate over-expression of normal oncogenes, or by the under-expression or disabling of tumor suppressor genes. Typically, changes in many genes are required to transform a normal cell into a cancer cell.
Genetic changes can occur at different levels and by different mechanisms. The gain or loss of an entire chromosome can occur through errors in mitosis. More common are mutations, which are changes in the nucleotide sequence of genomic DNA.
Large-scale mutations involve the deletion or gain of a portion of a chromosome. Genomic amplification occurs when a cell gains many copies (often 20 or more) of a small chromosomal locus, usually containing one or more oncogenes and adjacent genetic material. Translocation occurs when two separate chromosomal regions become abnormally fused, often at a characteristic location. A well-known example of this is the Philadelphia chromosome, or translocation of chromosomes 9 and 22, which occurs in chronic myelogenous leukemia, and results in production of the BCR-abl fusion protein, an oncogenic tyrosine kinase.
Small-scale mutations include point mutations, deletions, and insertions, which may occur in the promoter region of a gene and affect its expression, or may occur in the gene's coding sequence and alter the function or stability of its protein product. Disruption of a single gene may also result from integration of genomic material from a DNA virus or retrovirus, and resulting in the expression of viral oncogenes in the affected cell and its descendants.
Replication of the enormous amount of data contained within the DNA of living cells will probabilistically result in some errors (mutations). Complex error correction and prevention is built into the process, and safeguards the cell against cancer. If significant error occurs, the damaged cell can "self-destruct" through programmed cell death, termed apoptosis. If the error control processes fail, then the mutations will survive and be passed along to daughter cells.
Some environments make errors more likely to arise and propagate. Such environments can include the presence of disruptive substances called carcinogens, repeated physical injury, heat, ionising radiation, or hypoxia.
The errors which cause cancer are self-amplifying and compounding, for example:
*A mutation in the error-correcting machinery of a cell might cause that cell and its children to accumulate errors more rapidly.
*A further mutation in an oncogene might cause the cell to reproduce more rapidly and more frequently than its normal counterparts.
*A further mutation may cause loss of a tumour suppressor gene, disrupting the apoptosis signalling pathway and resulting in the cell becoming immortal.
*A further mutation in signaling machinery of the cell might send error-causing signals to nearby cells.
The transformation of normal cell into cancer is akin to a chain reaction caused by initial errors, which compound into more severe errors, each progressively allowing the cell to escape the controls that limit normal tissue growth. This rebellion-like scenario becomes an undesirable survival of the fittest, where the driving forces of evolution work against the body's design and enforcement of order. Once cancer has begun to develop, this ongoing process, termed clonal evolution drives progression towards more invasive stages.
==Diagnosis==
Most cancers are initially recognized either because of the appearance of signs or symptoms or through screening. Neither of these lead to a definitive diagnosis, which requires the examination of a tissue sample by a pathologist. People with suspected cancer are investigated with medical tests. These commonly include blood tests, X-rays, CT scans, and endoscopy.
===Classification===
Cancers are classified by the type of cell that the tumor cells resemble and is therefore presumed to be the origin of the tumor. These types include:
*Carcinoma: Cancers derived from epithelial cells. This group includes many of the most common cancers, particularly in the aged, and include nearly all those developing in the breast, prostate, lung, pancreas, and colon.
*Sarcoma: Cancers arising from connective tissue (i.e. bone, cartilage, fat, nerve), each of which develop from cells originating in mesenchymal cells outside the bone marrow.
*Lymphoma and leukemia: These two classes of cancer arise from hematopoietic (blood-forming) cells that leave the marrow and tend to mature in the lymph nodes and blood, respectively. Leukemia is the most common type of cancer in children accounting for about 30%.
*Germ cell tumor: Cancers derived from pluripotent cells, most often presenting in the testicles or the ovaries (seminoma and dysgerminoma, respectively).
*Blastoma: Cancers derived from immature "precursor" cells or embryonic tissue. Blastomas are more common in children than in older adults.
Cancers are usually named using -carcinoma, -sarcoma, or -blastoma as a suffix, with the Latin or Greek word for the organ or tissue of origin as the root. For example, cancers of the liver parenchyma arising from malignant epithelial cells is called hepatocarcinoma, while a malignancy arising from primitive liver precursor cells is called a hepatoblastoma, and a cancer arising from fat cells is called a liposarcoma. For some common cancers, the English organ name is used. For example, the most common type of breast cancer is called ductal carcinoma of the breast. Here, the adjective ductal refers to the appearance of the cancer under the microscope, which suggests that it has originated in the milk ducts.
Benign tumors (which are not cancers) are named using -oma as a suffix with the organ name as the root. For example, a benign tumor of smooth muscle cells is called a leiomyoma (the common name of this frequently occurring benign tumor in the uterus is fibroid). Confusingly, some types of cancer also use the -oma suffix, examples including melanoma and seminoma.
Some types of cancer are named for the size and shape of the cells under a microscope, such as giant-cell carcinoma, spindle cell carcinoma, and small-cell carcinoma.
===Pathology===
The tissue diagnosis given by the pathologist indicates the type of cell that is proliferating, its histological grade, genetic abnormalities, and other features of the tumor. Together, this information is useful to evaluate the prognosis of the patient and to choose the best treatment. Cytogenetics and immunohistochemistry are other types of testing that the pathologist may perform on the tissue specimen. These tests may provide information about the molecular changes (such as mutations, fusion genes, and numerical chromosome changes) that has happened in the cancer cells, and may thus also indicate the future behavior of the cancer (prognosis) and best treatment.
==Prevention==
Cancer prevention is defined as active measures to decrease the risk of cancer. The vast majority of cancer risk factors are due to environmental (including lifestyle) factors, and many of these factors are controllable. Thus, cancer is largely considered a preventable disease. Greater than 30% of cancer is considered preventable by avoiding risk factors including: tobacco, overweight/obesity, an insufficient diet, physical inactivity, alcohol, sexually transmitted infections, and air pollution. Not all environmental causes can be prevented completely such as naturally occurring background radiation.
===Dietary===
While many dietary recommendations have been proposed to reduce the risk of cancer, few have significant supporting scientific evidence. The primary dietary factors that increase risk are obesity and alcohol consumption; with a diet low in fruits and vegetables and high in red meat being implicated but not confirmed. Studies have linked consumption of red or processed meat to an increased risk of breast cancer, colon cancer, and pancreatic cancer, a phenomenon which could be due to the presence of carcinogens in foods cooked at high temperatures. Thus dietary recommendation for cancer prevention typically include: "mainly vegetables, fruit, whole grain and fish and a reduced intake of red meat, animal fat and refined sugar".
===Medication===
The concept that medications can be used to prevent cancer is attractive, and evidence supports their use in a few defined circumstances. In the general population non-steroidal anti-inflammatory drugs, such as aspirin and ibuprofen, reduce the risk of colorectal cancer however due to the cardiovascular and gastrointestinal side effects they cause overall harm when used for prevention. COX-2 inhibitor may decrease the rate of polyp formation in people with familial adenomatous polyposis however are associated with the same adverse effects as non-steroidal anti-inflammatories. Daily use of tamoxifen or raloxifene has been demonstrated to reduce the risk of developing breast cancer in high-risk women. The benefit versus harm for 5-alpha-reductase inhibitor such as finasteride is not clear.
Vitamins have not been found to be effective at preventing cancer, although low blood levels of vitamin D are correlated with increased cancer risk. Whether this relationship is causal and vitamin D supplementation is protective is not determined. Beta-carotene supplementation has been found to increase lung cancer rates in those who are high risk. Folic acid supplementation has not been found effective in preventing colon cancer and may increase colon polyps.
===Vaccination===
Vaccines have been developed that prevent some infection by some viruses. Human papillomavirus vaccine (Gardasil and Cervarix) decreases the risk of developing cervical cancer. The hepatitis B vaccine prevents infection with hepatitis B virus and thus decreases the risk of liver cancer.
==Screening==
Unlike diagnosis efforts prompted by symptoms and medical signs, cancer screening involves efforts to detect cancer after it has formed, but before any noticeable symptoms appear. This may involve physical examination, blood or urine tests, or medical imaging.
Cancer screening is currently not possible for many types of cancers, and even when tests are available, they may not be recommended for everyone. Universal screening or mass screening involves screening everyone. Selective screening identifies people who are known to be at higher risk of developing cancer, such as people with a family history of cancer. Several factors are considered to determine whether the benefits of screening outweigh the risks and the costs of screening. These factors include:
*Possible harms from the screening test: for example, X-ray images involve exposure to potentially harmful ionizing radiation.
*The likelihood of the test correctly identifying cancer.
*The likelihood of cancer being present: Screening is not normally useful for rare cancers.
*Possible harms from follow-up procedures.
*Whether suitable treatment is available.
*Whether early detection improves treatment outcomes.
*Whether the cancer will ever need treatment.
*Whether the test is acceptable to the people: If a screening test is too burdensome (for example, being extremely painful), then people will refuse to participate.
*Cost of the test.
===Recommendations===
The U.S. Preventive Services Task Force (USPSTF) strongly recommends cervical cancer screening in women who are sexually active and have a cervix at least until the age of 65. They recommend that Americans be screened for colorectal cancer via fecal occult blood testing, sigmoidoscopy, or colonoscopy starting at age 50 until age 75. There's insufficient evidence to recommend for or against screening for skin cancer, or prostate cancer in men under 75. Routine screening is not recommended for bladder cancer, testicular cancer, ovarian cancer, pancreatic cancer, or prostate cancer.
The USPSTF recommends mammography for breast cancer screening every two years for those 50–74 years old; however, they do not recommend either breast self-examination or clinical breast examination. A 2011 Cochrane review came to slightly different conclusions with respect to breast cancer screening stating that routine mammography may do more harm than good.
Japan screens for gastric cancer using photofluorography due to the high incidence there.
===Genetic testing===
Genetic testing for individuals at high-risk of certain cancers is recommended. Carriers of these mutations may than undergo enhanced surveillance, chemoprevention, or preventative surgery to reduce their subsequent risk.
==Management==
Many management options for cancer exist with the primary ones including: surgery, chemotherapy, radiation therapy, and palliative care. Which treatments are used depends upon the type, location and grade of the cancer as well as the person's health and wishes.
===Surgery===
Surgery is the primary method of treatment of most isolated solid cancers and may play a role in palliation and prolongation of survival. It's typically an important part of making the definitive diagnosis and staging the tumor as biopsies are usually required. Localized cancer surgery typically attempts to remove the entire mass along with, in certain cases, the lymph nodes in the area. For some types of cancer this is all that is needed for a good outcome.
===Chemotherapy===
Chemotherapy in addition to surgery has proven useful in a number of different cancer types including: breast cancer, colorectal cancer, pancreatic cancer, osteogenic sarcoma, testicular cancer, ovarian cancer, and certain lung cancers. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body.
===Radiation===
Radiation therapy involves the use of ionizing radiation in an attempt to either cure or improve the symptoms of cancer. It's used in about half of all cases and the radiation can be from either internal sources in the form of brachytherapy or external sources. Radiation is typically used in addition to surgery and or chemotherapy but for certain types of cancer such as early head and neck cancer may be used alone. For painful bone metastasis it has been found to be effective in about 70% of people.
===Alternative treatments===
Complementary and alternative cancer treatments are a diverse group of health care systems, practices, and products that are not part of conventional medicine. "Complementary medicine" refers to methods and substances used along with conventional medicine, while "alternative medicine" refers to compounds used instead of conventional medicine. Most complementary and alternative medicines for cancer have not been rigorously studied or tested. Some alternative treatments have been investigated and shown to be ineffective but still continue to be marketed and promoted.
===Palliative care===
Palliative care is an approach to symptom management that aims to reduce the physical, emotional, spiritual, and psycho-social distress experienced by people with cancer. Unlike treatment that's aimed at directly killing cancer cells, the primary goal of palliative care is to make the person feel better.
Palliative care is often confused with hospice and therefore only involved when people approach end of life. Like hospice care, palliative care attempts to help the person cope with the immediate needs and to increase the person's comfort. Unlike hospice care, palliative care does not require people to stop treatment aimed at prolonging their lives or curing the cancer.
Multiple national medical guidelines recommend early palliative care for people whose cancer has produced distressing symptoms (pain, shortness of breath, fatigue, nausea) or who need help coping with their illness. In people who have metastatic disease when first diagnosed, oncologists should consider a palliative care consult immediately. Additionally, an oncologist should consider a palliative care consult in any patient they feel has a prognosis of less than 12 months even if continuing aggressive treatment.
==Prognosis==
Cancer has a reputation as a deadly disease. Taken as a whole, about half of people receiving treatment for invasive cancer (excluding carcinoma in situ and non-melanoma skin cancers) die from cancer or its treatment. Survival is worse in the developing world. However, the survival rates vary dramatically by type of cancer, with the range running from basically all people surviving to almost no one surviving.
Those who survive cancer are at increased risk of developing a second primary cancer at about twice the rate of those never diagnosed with cancer. The increased risk is believed to be primarily due to the same risk factors that produced the first cancer, partly due to the treatment for the first cancer, and potentially related to better compliance with screening.
Predicting either short-term or long-term survival is difficult and depends on many factors. The most important factors are the particular kind of cancer and the patient's age and overall health. People who are frail with many other health problems have lower survival rates than otherwise healthy people. A centenarian is unlikely to survive for five years even if the treatment is successful. People who report a higher quality of life tend to survive longer. People with lower quality of life may be affected by major depressive disorder and other complications from cancer treatment and/or disease progression that both impairs their quality of life and reduces their lifespan. Additionally, patients with worse prognoses may be depressed or report a lower quality of life directly because they correctly perceive that their condition is likely to be fatal.
In 2007, the overall costs of cancer in the U.S. — including treatment and indirect mortality expenses (such as lost productivity in the workplace) — was estimated to be $226.8 billion. In 2009, 32% of Hispanics and 10% of children 17 years old or younger lacked health insurance. Uninsured patients and those from ethnic minorities are substantially more likely to be diagnosed with cancer at a later stage, when treatment can be more extensive and more costly.
==Epidemiology==
In 2008 approximately 12.7 million cancers were diagnosed (excluding non-melanoma skin cancers and other non-invasive cancers) and 7.6 million people died of cancer worldwide. Cancers as a group account for approximately 13% of all deaths each year with the most common being: lung cancer (1.4 million deaths), stomach cancer (740,000 deaths), liver cancer (700,000 deaths), colorectal cancer (610,000 deaths), and breast cancer (460,000 deaths). This makes invasive cancer the leading cause of death in the developed world and the second leading cause of death in the developing world. Over half of cases occur in the developing world.
Global cancer rates have been increasing primarily due to an aging population and lifestyle changes in the developing world. The most significant risk factor for developing cancer is old age. Although it's possible for cancer to strike at any age, most people who are diagnosed with invasive cancer are over the age of 65. According to cancer researcher Robert A. Weinberg, "If we lived long enough, sooner or later we all would get cancer." Some of the association between aging and cancer is attributed to immunosenescence, errors accumulated in DNA over a lifetime, and age-related changes in the endocrine system.
Some slow-growing cancers are particularly common. Autopsy studies in Europe and Asia have shown that up to 36% of people have undiagnosed and apparently harmless thyroid cancer at the time of their deaths, and that 80% of men develop prostate cancer by age 80. As these cancers did not cause the person's death, identifying them would have represented overdiagnosis rather than useful medical care.
The three most common childhood cancers are leukemia (34%), brain tumors (23%), and lymphomas (12%). Rates of childhood cancer have increased by 0.6% per year between 1975 to 2002 in the United States and by 1.1% per year between 1978 and 1997 in Europe.
==History==
The earliest written record regarding cancer is from 3000 B.C.E. in the Egyptian Edwin Smith Papyrus and describes cancer of the breast. Cancer however has existed for all of human history. Hippocrates (ca. 460 B.C.E. – ca. 370 B.C.E.) described several kinds of cancer, referring to them with the Greek word carcinos (crab or crayfish). This name comes from the appearance of the cut surface of a solid malignant tumour, with "the veins stretched on all sides as the animal the crab has its feet, whence it derives its name". The Greek, Celsus (ca. 25 B.C.E. – 50 C.E.) translated carcinos into the Latin cancer, also meaning crab and recommended surgery as treatment. Galen (2nd century C.E.) disagreed with the use of surgery and recommended emetics instead. These recommendations largely stood for 1000 years.
In the 15th, 16th, and 17th centuries, it became more acceptable for doctors to dissect bodies to discover the cause of death. The German professor Wilhelm Fabry believed that breast cancer was caused by a milk clot in a mammary duct. The Dutch professor Francois de la Boe Sylvius, a follower of Descartes, believed that all disease was the outcome of chemical processes, and that acidic lymph fluid was the cause of cancer. His contemporary Nicolaes Tulp believed that cancer was a poison that slowly spreads, and concluded that it was contagious.
The physician John Hill described tobacco snuff as the cause of nose cancer in 1761. This was followed by the report in 1775 by British surgeon Percivall Pott that cancer of the scrotum was a common disease among chimney sweeps. With the widespread use of the microscope in the 18th century, it was discovered that the 'cancer poison' spread from the primary tumor through the lymph nodes to other sites ("metastasis"). This view of the disease was first formulated by the English surgeon Campbell De Morgan between 1871 and 1874.
==Society and culture==
Though many diseases (such as heart failure) may have a worse prognosis than most cases of cancer, cancer is the subject of widespread fear and taboos. The euphemism, "after a long illness" is still commonly used (2012) reflecting an apparent stigma. This deep belief that cancer is necessarily a difficult and usually deadly disease is reflected in the systems chosen by society to compile cancer statistics: the most common form of cancer—non-melanoma skin cancers, accounting for about one-third of all cancer cases worldwide, but very few deaths —are excluded from cancer statistics specifically because they are easily treated and almost always cured, often in a single, short, outpatient procedure.
Cancer is regarded as a disease that must be "fought" to end the "civil insurrection"; a "War on Cancer" has been declared. Military metaphors are particularly common in descriptions of cancer's human effects, and they emphasize both the parlous state of the affected individual's health and the need for the individual to take immediate, decisive actions himself, rather than to delay, to ignore, or to rely entirely on others caring for him. The military metaphors also help rationalize radical, destructive treatments.
In the 1970s, a relatively popular alternative cancer treatment was a specialized form of talk therapy, based on the idea that cancer was caused by a bad attitude. People with a "cancer personality"—depressed, repressed, self-loathing, and afraid to express their emotions—were believed to have manifested cancer through subconscious desire. Some psychotherapists said that treatment to change the patient's outlook on life would cure the cancer. Among other effects, this belief allows society to blame the victim for having caused the cancer (by "wanting" it) or having prevented its cure (by not becoming a sufficiently happy, fearless, and loving person). It also increases patients' anxiety, as they incorrectly believe that natural emotions of sadness, anger or fear shorten their lives. The idea was excoriated by the notoriously outspoken Susan Sontag, who published Illness as Metaphor while recovering from treatment for breast cancer in 1978. Although the original idea is now generally regarded as nonsense, the idea partly persists in a reduced form with a widespread, but incorrect, belief that deliberately cultivating a habit of positive thinking will increase survival. This notion is particularly strong in breast cancer culture.
==Research==
Because cancer is a class of diseases, it's unlikely that there will ever be a single "cure for cancer" any more than there will be a single treatment for all infectious diseases. Angiogenesis inhibitors were once thought to have potential as a "silver bullet" treatment applicable to many types of cancer, but this has not been the case in practice.
Experimental cancer treatments are treatments that are being studied to see whether they work. Typically, these are studied in clinical trials to compare the proposed treatment to the best existing treatment. They may be entirely new treatments, or they may be treatments that have been used successfully in one type of cancer, and are now being tested to see whether they are effective in another type. More and more, such treatments are being developed alongside companion diagnostic tests to target the right drugs to the right patients, based on their individual biology.
Cancer research is the intense scientific effort to understand disease processes and discover possible therapies.
Research about cancer causes focuses on the following issues:
*Agents (e.g. viruses) and events (e.g. mutations) which cause or facilitate genetic changes in cells destined to become cancer.
*The precise nature of the genetic damage, and the genes which are affected by it.
*The consequences of those genetic changes on the biology of the cell, both in generating the defining properties of a cancer cell, and in facilitating additional genetic events which lead to further progression of the cancer.
The improved understanding of molecular biology and cellular biology due to cancer research has led to a number of new, effective treatments for cancer since President Nixon declared "War on Cancer" in 1971. Since 1971 the United States has invested over $200 billion on cancer research; that total includes money invested by public and private sectors and foundations. Despite this substantial investment, the country has seen a five percent decrease in the cancer death rate (adjusting for size and age of the population) between 1950 and 2005.
==In pregnancy==
Because cancer is largely a disease of older adults, it's not common in pregnant women. Cancer affects approximately 1 in 1,000 pregnant women. The most common cancers found during pregnancy are the same as the most common cancers found in non-pregnant women during childbearing ages: breast cancer, cervical cancer, leukemia, lymphoma, melanoma, ovarian cancer, and colorectal cancer.
Diagnosing a new cancer in a pregnant woman is difficult, in part because any symptoms are commonly assumed to be a normal discomfort associated with pregnancy. As a result, cancer is typically discovered at a somewhat later stage than average in many pregnant or recently pregnant women. Some imaging procedures, such as MRIs, CT scans, ultrasounds, and mammograms with fetal shielding are considered safe during pregnancy; some others, such as PET scans are not.
Treatment is generally the same as for non-pregnant women. However, radiation and radioactive drugs are normally avoided during pregnancy, especially if the fetal dose might exceed 100 cGy. In some cases, some or all treatments are postponed until after birth if the cancer is diagnosed late in the pregnancy. Early deliveries to speed the start of treatment are not uncommon. Surgery's generally safe, but pelvic surgeries during the first trimester may cause miscarriage. Some treatments, especially certain chemotherapy drugs given during the first trimester, increase the risk of birth defects and pregnancy loss (spontaneous abortions and stillbirths).
Elective abortions are not required and, for the most common forms and stages of cancer, do not improve the likelihood of the mother surviving or being cured. In a few instances, such as advanced uterine cancer, the pregnancy cannot be continued, and in others, such as an acute leukemia discovered early in pregnancy, the pregnant woman may choose to have abortion so that she can begin aggressive chemotherapy without worrying about birth defects.
Some treatments may interfere with the mother's ability to give birth vaginally or to breastfeed her baby. Cervical cancer may require birth by Caesarean section. Radiation to the breast reduces the ability of that breast to produce milk and increases the risk of mastitis. Also, when chemotherapy is being given after birth, many of the drugs pass through breast milk to the baby, which could harm the baby.
==Modern controversy==
For the past forty years, emphasis in cancer treatment has been focused on both prevention (generally lifestyle changes) and early detection and treatment. Although preventative measures have been largely effective, medical science is now questioning the utility of attempting to detect cancer at its earliest stages. To do so requires frequent testing, and the chances of a false positive often outweigh the benefits of early detection. In addition, studies are beginning to show that cancers caught in the "early stage" may in fact resolve on their own without treatment and that monitoring rather than immediate treatment may be a better option.
Moreover, many cancers move so quickly that the testing frequency required to ensure effective early treatment would be impractical. In addition, many cancer detection methods, such as the mammogram, expose patients to radiation which, in and of itself, may increase cancer risks if widely adopted.
In another example, the blood test for early stage prostate cancer is being questioned as to its effectiveness. Prostate cancer is generally slow growing and can be treated even if it's only detected through a rectal exam. Clinical trials are beginning to show that patients who have a positive blood test who are not treated (and are only monitored for further symptoms) have a better quality of life and similar lifespan to persons who receive immediate surgery or radiation therapy, both of which have serious side effects including a high risk of erectile dysfunction. Epidemiological studies of prostate cancer patients in the United States compared to the United Kingdom show that although U.S. patients are, on average, diagnosed five years earlier than their U.K. counterparts, the life expectancy and mortality rate of patients in both countries are nearly identical. In addition, the average age of diagnosis of U.S. patients is 65 compared to 70 in U.K. patients, a group that in both cases has a limited life expectancy.
==On the series==
The importance of Cancer to the series cannot be underestimated. It's fundamental to the personality of House's best friend James Wilson, being both his medical specialty and the eventual cause of his death. It's also, by far, the most common final diagnosis on the series - 16 patients in all, about 2 every season. It consistently appears as a differential diagnosis as well, being considered in almost every episode. Many characters living with cancer have had major impacts on the lives of the characters.
===As the final diagnosis===
*Lucy Palmeiro - The Socratic Method - Liver Cancer - Treated
*Naomi Randolph - Babies & Bathwater - Small-cell carcinoma - Terminal
*Volleyball Player - Three Stories - Bone Cancer - Treated
*Sebastian Charles - TB or Not TB - Nesidioblastoma- Treated
*Alex - Skin Deep - Testicular Cancer - Treated
*Kara Mason - Forever - Stomach Cancer secondary to Celiac disease - Patient refused treatment
*George - Que Será Será - Small-cell carcinoma - Terminal
*Abigail Ralphean - Merry Little Christmas - Langerhans cell histiocytosis - Treated (Lung Cancer was also an early differential, and Cameron and Wilson got into an argument about whether the illness was cancer or an autoimmune condition).
*Derek Hoyt - Words and Deeds - Spinal Meningioma - Treated
*Maggie - It's a Wonderful Lie - Breast Cancer - Treated
*Apple - Not Cancer - Stem cell Cancer - Treated
*Sophia Isabel Velez - Emancipation - Acute promyelocytic leukemia - Treated
*Morgan West - Here Kitty - Appendix Cancer - Treated
*Eugene Schwartz - Both Sides Now - Pancreatic Cancer - Unknown
*Tucker - Wilson - Acute lymphoblastic leukemia - Treated
*Daryl - Moving the Chains - Melanoma - Treated
*Abbey's baby and Abbey - Unplanned Parenthood - Melanoma and Small-cell carcinoma - One treated, one fatal
*Kendall Pearson - Last Temptation - Lymphosarcoma - Treated
*Cyrus Harry - Changes - Teratoma - Treated
*Terry Foley - The Fix - Glomus tumor - Treated
*Iris - Dead & Buried - Choriocarcinoma - Treated
*Bill Koppelman - Nobody's Fault - Lymph node tumor - Treated
*Emily Lawson - The C Word - Atrial myxoma - Treated
===As a differential diagnosis===
*Rebecca Adler - Pilot - Neurological symptoms pointed to Brain Cancer
*Elise Snow - Fidelity - hypersomnia blamed on paraneoplastic syndrome from Breast Cancer
*Victoria Madsen - Histories - Mass on scan mistaken for Ovarian Cancer
*Keith Foster - Detox - Family history of Pancreatic Cancer
*Hank Wiggen - Sports Medicine - Osteopenia most likely due to Bone Cancer
*Carly Forlano - Control - Leg pain pointed to Bone Cancer or Colon Cancer
*Gary H. Wright - Role Model - The only other explanation for his toxoplasmosis other than AIDS was cancer
*Mary Carroll - Kids - Bone cancer explained her neck stiffness
*Jeff Forrester - Spin - Blood cancer would explain his sudden weakness. Forrester's manager leaks this information to the press in order to alleviate suspicion that he has been cheating.
*Anica Jovanovich - Deception - A mass on her pancreas was though to be Pancreatic Cancer given her other symptoms.
*Henry Arrington - Sex Kills - Henry's swollen testicles pointed immediately to Testicular Cancer, but Foreman quickly ruled it out.
*Ian Alston - All In - A cancer of the blood, such as leukemia, would explain Ian's respiratory distress. However, Wilson soon ruled it out.
*Hannah - Sleeping Dogs Lie - Cancer would explain her hypersomnia, but she had just had a transplant and they had to stop her immunosuppressants to do a proper workup.
*Vince - No Reason - The patient's burst testicle pointed to Testicular Cancer
*Adam Kelvey - Lines in the Sand - The loose liver cells in Adam's lymph nodes pointed to Liver Cancer.
*Fran - Airborne - Breast Cancer would explain her sudden loss of consciousness.
*Lucy and Jasper - Act Your Age - A hormone secreting tumor would explain their illness, but it's unlikely they would both develop one at the same time.
*Lupe - House Training - Failures of multiple systems pointed to cancer and the need for total body irradiation. However, the treatment led to the patient's death when it turned out to be sepsis.
*Greta Cooper - The Right Stuff - House uses his stethoscope and percussion and finds a mass in her chest that could be Lung Cancer.
*Thomas Stark - 97 Seconds - The patient's symptoms could be explained by a Melanoma.
*John - Whatever It Takes - The skin condition and weight loss could be explained by Blood Cancer.
*Cate Milton - Frozen - Her abdominal pain could be explained by an abdominal tumor.
*Lou - Dying Changes Everything - The patient's symptoms pointed to Leukemia and it could not be ruled out in the differential.
*Nicole - Birthmarks - The patient's DIC could have indicated cancer.
*Jona - Emancipation - The patient's symptoms could be explained by cancer.
*Jason - Last Resort - The patient's distended jugular vein and sweating on only one side of his face pointed to Lung Cancer.
*Dana Miller - The Greater Good - The patient started feeling shocks which pointed to a hemangioma. When the scans shown multiple masses, they started thinking it's mesothelioma.
*Daniel Bresson - Unfaithful - Cancer explained his hallucinations and other symptoms.
*Lee - Locked In - House thought the mass on his brain scans was a tumor.
*Doug Svensen - Saviors - His broken bone without sign of trauma pointed to cancer.
*Seth - House Divided - House thought Seth's deafness might be due to NF2 cancer.
*Penelope - Under My Skin - The patient's symptoms point to Liver Cancer.
*Scott - Both Sides Now - While being taunted by the Amber hallucination, House thinks that Scott's excessive sweating points to Pancreatic Cancer. However, he later realizes that the reason his subconscious was thinking that was because of the clinic patient Eugene Schwartz has a large stomach and "squawks". It turns out Eugene has Pancreatic Cancer.
*Jack Randall - Instant Karma - An asymmetrical buildup of fluid points to both Brain Cancer and Stomach Cancer.
*Donny - Brave Heart - Donny's tooth pain without a seeming cause pointed to Bone Cancer.
*Frankie - Private Lives - A biopsy of her burst appendix seemed to confirm Lymphoma.
*Abby Nash - Black Hole - Multiple organ failure pointed to cancer.
*Sir William - Knight Fall - Kidney failure pointed to Liver Cancer.
*Niles - A Pox on Our House - House believes the patient's poor reaction to the smallpox vaccine is the result of a return of his Kidney Cancer, making him immunocompromised.
*Arlene Cuddy - Family Practice - Marty Kaufman runs several biopsies thinking Arlene might have cancer.
*Phillip Wright - Two Stories - The team has to rule out cancer as a reason why the patient has literally coughed up a lung.
*Afsoun Hamidi - Moving On - House realizes the patient's performance piece where she shaved her head was to hide chemotherapy side effects. He does a scan and finds a mass which he believes is lymphoma.
*Nick - Twenty Vicodin - The patient's broken bones and his smoking point to Lung Cancer.
*Stevie Weathers - Transplant - A mass in his arm was thought to be a tumor.
*Ben Parker - Parents - A swelling in the patient's eye pointed to Burkitt's lymphoma.
*Moira Parker - Chase - The patient's increasingly severe symptoms point to Lymphoma.
*Dr. Peter Treiber - Post Mortem - The patient's increasingly severe abdominal pain points to Bowel Cancer.
===Other key appearances===
*Allison Cameron's first husband died of thyroid cancer. Cameron knew about the diagnosis before she married him, and that it was terminal.
*Rowan Chase comes to Princeton-Plainsboro Teaching Hospital in Cursed to get a consult from Wilson for his lung cancer. He does not reveal his condition to his son, but House sees the tattoo that's used to guide radiation therapy. Chase only finds out in The Mistake when he's told his father has died.
*Edward Vogler says the reason he gave the hospital $100 million was in order to try to find new treatments for cancer and other terminal diseases. In Babies & Bathwater, House dreams about telling Vogler he has cancer.
*In Acceptance, Cameron must come to terms with a diagnosis of terminal cancer for Cindy Kramer. However, she tries fruitlessly to find another diagnosis despite being admonished by both House and Wilson. She also avoids breaking the news to the patient because the patient has no family. It turns out that one of the reasons Cameron married her first husband despite his cancer diagnosis was the fact that he had no family either.
*In Autopsy, Andie was suffering from alveolar rhabdomyosarcoma.
*In TB or Not TB, a clinic patient named Cecilia Carter was sure the lump she had was breast cancer. When Foreman saw her, he was wearing House's name badge because he was covering his clinic hours. Foreman tried to reassure Ms. Carter that the lump she found was benign and she didn't need a biopsy, but Ms. Carter insisted. The biopsy was negative (and as Foreman pointed out, unnecessary) but Ms. Carter complained to Cuddy about "Dr. House's" conduct. When Cuddy confronted House, he pointed out (again correctly) that he was being picked on and that if the patient had complained about Foreman, Cuddy would have brushed it off. House then told Foreman he had no business being rude to patients until his medical skills got as good as House's.
*In The Mistake, Kayla McGinley accidentally gets a hepatoma when she gets a live liver transplant from her brother Sam.
*Grace Palmieri, who only appears in House vs. God is one of the key characters in the series nevertheless. Grace has terminal liver cancer and was Wilson's patient. She missed her ride home one evening and Wilson both agreed to take her home and buy her groceries. They wound up sleeping together and, unbeknownst to House, when Wilson moved out of House's apartment after his third divorce, he moved in with Grace. Grace's cancer started to shrink after she was touched by the faith healer Boyd. Curious, House had Chase do an environmental scan of Grace's apartment to see if anything else could have affected the cancer. When Chase found men's clothes in Grace's apartment, House put it all together and realized Wilson was living there. House eventually figured out that Boyd had herpes, which had temporarily attacked Grace's cancer, giving her a few more months of life and temporarily better life quality.
*In the following episode, Euphoria (Part 1), when Foreman gets sick with the same disease that the patient has, House reacts to Wilson's reassurance by reminding Wilson that you can even have unprotected sex with a cancer patient and not worry about getting the disease.
*In Forever, House becomes curious about Cuddy's sudden interest in Wilson. He searches her garbage and finds red clover, which is used to treat cancer. He tells Wilson that Cuddy is probably looking for a consult. Wilson brushes off the suggestion, but when he does go to dinner with Cuddy, he steals her spoon so he can check her saliva for cancer markers. It's negative. In fact, Cuddy was sizing up Wilson hoping he might be a sperm donor for artificial insemination.
*In Meaning, Richard McNeil was a brain cancer survivor who was uncommunicative and could only move his hand enough to operate an electric wheelchair. After he drove himself into a pool, House agreed to take his case. After taking some obvious steps to alleviate discomfort, House becomes obsessed that Richard has some underlying condition that's keeping him confined to a wheelchair. Over the objections of his team and Cuddy, but with the cooperation of the patient's wife, House performs a series of increasingly dangerous, but fruitless, tests. However, while cooling himself in a fountain, he thinks that Richard may have Addison's disease. He begs Cuddy to give him a shot of cortisol - a safe procedure. However, she refuses, reminding him that patient's aren't experimental subjects. However, Cuddy gives into temptation and gives Richard the shot just before he's discharged. After a few seconds, Richard unbuckles the belt of his wheelchair and manages to stand and hug his wife. However, Wilson convinces Cuddy that she must keep this information from House or else he will feel the rules don't apply to him. When Cameron learns that Richard has recovered, she blames House's lack of courage on his failure in the case and tells Cuddy she must tell House the truth. When House runs out of ideas on his next case, Cuddy finally does and House has a brilliant idea that successfully treats the patient.
*In One Day, One Room, Cameron comes across a homeless clinic patient with a discharge slip from another hospital saying he has terminal cancer. She realizes his death is imminent. He asks if he can stay the night and she admits him. However, the patient refuses palliative care because he does not want to die without someone remembering him. Cameron gets increasingly frustrated as she tries to convince the man to accept treatment.
*In Half-Wit, House fakes having cancer by copying files from a patient he does think has brain cancer. He arranges to have a treatment where a drug will be injected directly into the pleasure center of his brain. However, the team finds out he's heading to Boston to see a cancer specialist and work double time to find another diagnosis despite House telling them not to do so. The team succeeds and prove it's just tertiary syphilis which can be treated with antibiotics. However, they call Boston to give them to the good news without telling House, who has to reveal the deception and earn the fury of the team.
*In Family, the team try to diagnose Matty so he can donate bone marrow to his brother Nick to treat leukemia.
*In Alone, House gets back at Wilson for kidnapping his guitar by hiding one of his patients, Sam Lee. When Wilson gets angry and tells House that it could lead to a hospital mix-up, House realizes the patient he's treating may also have been misidentified.
*When Foreman runs his own diagnostic department at New York Mercy Hospital in 97 Seconds, he diagnoses his patient with aggressive lymphoma, but his supervisor wants him to rule out infection before giving the patient radiation therapy. Foreman knows that ruling out infection will allow the cancer to spread so it will be untreatable, so he goes against orders and takes the patient for radiation himself. The patient quickly improves, but Foreman gets fired.
*In Games, Wilson finds out he has misdiagnosed a patient, McKenna, and can tell him he will live a normal lifespan. House is there to watch when Wilson breaks the news (one of the few times in the series House wears a lab coat). However, the patient is actually disappointed - he has to pay the commission on the recent sale of his house. Wilson later tries to reimburse him for the commission, but the patient refuses because House has told him he can get a lot more money if he sues.
*In Lucky Thirteen, they mention the movie Brian's Song, part of which is about the death of football player Brian Piccolo from cancer.
*The patient in The Greater Good, Dana Miller was once a top cancer researcher. However, after a brush with uterinemyoma, she gave up being a doctor to try to become a chef. Wilson is heartbroken when he finds out as he felt that she had a very good chance of making a breakthrough.
*In The Greater Good, Remy Hadley develops a brain tumor, most likely because of the experimental drug she was taking for her Huntington's disease. She's given radiation seed therapy and recovers.
*In The Social Contract, Audrey Greenwald, the wife of the patient, is organizing a walk to raise funding for breast cancer.
*Also in The Social Contract, as House tries to find out what Wilson is hiding from him, he finds that Wilson may be speaking to a doctor at New York Mercy who specializes in dealing with suicide in cancer patients.
*In Simple Explanation, Eddie Novack is admitted with a diagnosis of terminal cancer. However, Cameron sees nodules that aren't consistent with that diagnosis and goads House into trying to prove the original doctor wrong. House does the tests and finds Eddie actually has treatable blastomycosis.
*In Under My Skin, House bursts in on Wilson when Wilson is breaking the news to Mr. Pietramalla that he has kidney cancer. Wilson tries to throw House out but backs off when House blurts out he's been having hallucinations.
*In 5 to 9, Cuddy is in the clinic when she comes across a patient, Hall, who wants a prescription for breast milk to treat his colon cancer. He says he can get it, but can't afford it without insurance. Cuddy knows that his insurance company won't pay even if he does have a prescription, and turns him down. However, House informs her that Hall got another doctor to write the prescription.
*Also in 5 to 9, it appears House's unseen patient Mr. Plutus may have cancer as well. House wants to give him malaria to treat it and tries to convince Cuddy to let him try it. However, the real reason he wants permission is to win a $50 bet with Wilson.
*In Small Sacrifices, the patient Ramon Silva re-enacts the crucifixion every year to thank God for the spontaneous remission of his daughter's cancer. However, when it's learned his has Marburg multiple sclerosis, he refuses the treatment because it's based on stem cells harvested from aborted fetuses. To get him to agree to treatment, House tricks him into thinking his daughter's cancer has returned.
*One of the most important appearances of the disease is in Bombshells where Cuddy's cancer scare leads to the breakup of her relationship with House. House tries to reassure Cuddy at every stage, only to have each subsequent step in the process point closer to cancer. He finds himself unable to be supportive until he turns to Vicodin. After the cancer turns out to be a combination of a harmless tumor and inflammation from an allergy to antibiotics, Cuddy still breaks up with House once she realizes he returned to Vicodin.
*In After Hours, House realizes he has developed several small tumors after using an experimental muscle building drug. He tries to excise them himself and, when he can't continue or reach Wilson or his team, he has to call Cuddy. She takes him to the hospital for proper treatment.
*Also in After Hours, after his run in with a stripper, Taub tells Ruby about a former patient who was in for a tummy tuck who turned out to have cancer. The patient took the news well because he was proud of his grown children. Taub tells Ruby that he wants to have that feeling and agrees to support his child that's now being carried by Ruby.
*In Transplant, the reason they are trying to save Stevie Weathers' lungs is to give them to Vanessa, a breast cancer survivor.
*In Love is Blind, House's mother Blythe tricks Wilson into thinking she has cancer so House will feel compelled to visit her.
===The End===
The producers decided to make cancer the key plot point to end the series. In Body and Soul, Wilson breaks the news to House that he has a Stage II Thymoma, a life threatening form of cancer. At first, House thinks Wilson is getting back at him, but soon realizes he's serious.
In The C Word, House decides to take time off in order to help Wilson through his treatment. However, after Wilson refuses conventional therapy, House does some digging and finds out Wilson has approached several other oncologists who made exactly the same recommendation. He realizes Wilson is going to try something drastic, and finds that Wilson has been hoarding chemotherapy drugs in his office. He also realizes Wilson is planning to give himself a massive dose of chemotherapy to ensure the thymoma shrinks so he can have surgery to remove the remaining tumor. However, House also realizes a dose that high is as likely to kill him as an untreated thymoma. Once he realizes that Wilson is serious, he agrees to treat him. Wilson survives the treatment with House's help, and House even gives Wilson some of his precious Vicodin to help him through the pain.
After an eventful road trip in Post Mortem, House performs the scan on Wilson's thymus gland to see the results of the extreme chemotherapy. Unfortunately, the chemotherapy has had no effect at all and the thymoma remains inoperable.
In Holding On, Hilson is stretched to the limit when Wilson refuses further treatment and House presses for it. After several fights and a good deal of back and forth, House finally accepts Wilson's decision and they decide to make the best of their remaining time together. However, due to a disastrous prank played by House, he's facing a return to prison to get out just after Wilson will most likely be dead.
In the final episode, Everybody Dies, House tries numerous schemes to avoid going to prison, all of which fail. However, he does find a way to stay out of jail during Wilson's remaining days.
==In other languages==
Language 	Name
Spanish 	Cáncer
French 	Cancer
Italian 	Tumore
Deutsch 	Krebs
Portuguese	Câncer
This article was largely developed from the article of the same name at Wikipedia.
Cancer at NIH
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