dimanche 13 octobre 2013
samedi 12 octobre 2013
What is the TNM system?
The TNM system is one of the most widely used cancer staging systems. This system has been accepted by the Union for International Cancer Control (UICC) and the American Joint Committee on Cancer (AJCC). Most medical facilities use the TNM system as their main method for cancer reporting.
The TNM system is based on the size and/or extent (reach) of the primary tumor (T), the amount of spread to nearby lymph nodes (N), and the presence of metastasis (M) or secondary tumors formed by the spread of cancer cells to other parts of the body. A number is added to each letter to indicate the size and/or extent of the primary tumor and the degree of cancer spread.
Primary Tumor (T)
TX: Primary tumor cannot be evaluated
T0: No evidence of primary tumor
Tis: Carcinoma in situ (CIS; abnormal cells are present but have not spread to neighboring tissue; although not cancer, CIS may become cancer and is sometimes called preinvasive cancer)
T1, T2, T3, T4: Size and/or extent of the primary tumor
Regional Lymph Nodes (N)
NX: Regional lymph nodes cannot be evaluated
N0: No regional lymph node involvement
N1, N2, N3: Degree of regional lymph node involvement (number and location of lymph nodes)
Distant Metastasis (M)
MX: Distant metastasis cannot be evaluated
M0: No distant metastasis
M1: Distant metastasis is present
For example, breast cancer classified as T3 N2 M0 refers to a large tumor that has spread outside the breast to nearby lymph nodes but not to other parts of the body. Prostate cancer T2 N0 M0 means that the tumor is located only in the prostate and has not spread to the lymph nodes or any other part of the body.
For many cancers, TNM combinations correspond to one of five stages. Criteria for stages differ for different types of cancer. For example, bladder cancer T3 N0 M0 is stage III, whereas colon cancer T3 N0 M0 is stage II.StageDefinitionStage 0Carcinoma in situStage I, Stage II, and Stage IIIHigher numbers indicate more extensive disease: Larger tumor size and/or spread of the cancer beyond the organ in which it first developed to nearby lymph nodes and/or tissues or organs adjacent to the location of the primary tumorStage IVThe cancer has spread to distant tissues or organs
Question 6 describes sources of additional information about staging for specific types of cancer.
Are all cancers staged with TNM classifications?
Most types of cancer have TNM designations, but some do not. For example, cancers of the brain and spinal cord are staged according to their cell type and grade. Different staging systems are also used for many cancers of the blood or bone marrow, such as lymphomas. The Ann Arbor staging classification is commonly used to stage lymphomas and has been adopted by both the AJCC and the UICC. However, other cancers of the blood or bone marrow, including most types of leukemia, do not have a clear-cut staging system. Another staging system, developed by the International Federation of Gynecology and Obstetrics (FIGO), is used to stage cancers of the cervix, uterus, ovary, vagina, and vulva. This system is also based on TNM information. Additionally, most childhood cancers are staged using either the TNM system or the staging criteria of the Children’s Oncology Group (COG), which conducts pediatric clinical trials; however, other staging systems may be used for some childhood cancers.
Many cancer registries, such as those supported by NCI’s Surveillance, Epidemiology, and End Results (SEER) Program, use
After being trained and certified as a specialist, a physician may choose to become a subspecialist. A subspecialist has at least 1 additional year of full-time education in a particular area of a specialty. This training is designed to increase the physician’s expertise in a specific field. Specialists can be board certified in their subspecialty as well.
The following are some specialties and subspecialties that pertain to cancer treatment:Medical Oncology is a subspecialty of internal medicine. Doctors who specialize in internal medicine treat a wide range of medical problems. Medical oncologists treat cancer and manage the patient’s course of treatment. A medical oncologist may also consult with other physicians about the patient’s care or refer the patient to other specialists.Hematology is a subspecialty of internal medicine. Hematologists focus on diseases of the blood and related tissues, including the bone marrow, spleen, and lymph nodes.Radiation Oncology is a subspecialty of radiology. Radiology is the use of x-rays and other forms of radiation to diagnose and treat disease. Radiation oncologists specialize in the use of radiation to treat cancer.Surgery is a specialty that pertains to the treatment of disease by surgical operation. General surgeons perform operations on almost any area of the body. Physicians can also choose to specialize in a certain type of surgery; for example, thoracic surgeons are specialists who perform operations specifically in the chest area, including the lungs and the esophagus.
The American Board of Medical Specialties
Clear patterns have emerged between alcohol consumption and the development of the following types of cancer:Head and neck cancer: Alcohol consumption is a major risk factor for certain head and neck cancers, particularly cancers of the oral cavity (excluding the lips), pharynx (throat), and larynx (voice box) (4). People who consume 50 or more grams of alcohol per day (approximately 3.5 or more drinks per day) have at least a two to three times greater risk of developing these cancers than nondrinkers (4). Moreover, the risks of these cancers are substantially higher among persons who consume this amount of alcohol and also use tobacco (5).Esophageal cancer: Alcohol consumption is a major risk factor for a particular type of esophageal cancer called esophageal squamous cell carcinoma (2). In addition, people who inherit a deficiency in an enzyme that metabolizes alcohol have been found to have substantially increased risks of alcohol-related esophageal squamous cell carcinoma (see Question 5).Liver cancer: Alcohol consumption is an independent risk factor for, and a primary cause of, liver cancer (hepatocellular carcinoma) (6). (Chronic infection with hepatitis B virus and hepatitis C virus are the other major causes of liver cancer.)Breast cancer: More than 100 epidemiologic studies have looked at the association between alcohol consumption and the risk of breast cancer in women. These studies have consistently found an increased risk of breast cancer associated with increasing alcohol intake. A meta-analysis of 53 of these studies (which included a total of 58,000 women with breast cancer) showed that women who drank more than 45 grams of alcohol per day (approximately three drinks) had 1.5 times the risk of developing breast cancer as nondrinkers (a modestly increased risk) (7). The risk of breast cancer was higher across all levels of alcohol intake: for every 10 grams of alcohol consumed per day (slightly less than one drink), researchers observed a small (7 percent) increase in the risk of breast cancer. The Million Women Study in the United Kingdom (which included more than 28,000 women with breast cancer) provided a more recent, and slightly higher, estimate of breast cancer risk at low to moderate levels of alcohol consumption: every 10 grams of alcohol consumed per day was associated with a 12 percent increase in the risk of breast cancer (8).Colorectal cancer: Alcohol consumption is associated with a modestly increased risk of cancers of the colon and rectum. A meta-analysis of 57 cohort and case-control studies that examined the association between alcohol consumption and colorectal cancer risk showed that people who regularly drank 50 or more grams of alcohol per day (approximately 3.5 drinks) had 1.5 times the risk of developing colorectal cancer as nondrinkers or occasional drinkers (9). For every 10 grams of alcohol consumed per day, there was a small (7 percent) increase in the risk of colorectal cancer.
Research on alcohol consumption and other cancers:
Numerous studies have examined the association between alcohol consumption and the risk of other cancers, including cancers of the pancreas, ovary, prostate, stomach, uterus, and bladder. For these cancers, either no association with alcohol use has been found or the evidence for an association is inconsistent.
However, for two cancers
What is computed tomography?
Computed tomography (CT) is an imaging procedure that uses special x-ray equipment to create detailed pictures, or scans, of areas inside the body. It is also called computerized tomography and computerized axial tomography (CAT).
The term tomography comes from the Greek words tomos (a cut, a slice, or a section) and graphein (to write or record). Each picture created during a CT procedure shows the organs, bones, and other tissues in a thin
For patients with cancer, biological therapies may be used to treat the cancer itself or the side effects of other cancer treatments. Although many forms of biological therapy have been approved by the U.S. Food and Drug Administration (FDA), others remain experimental and are available to cancer patients principally through participation in clinical trials (research studies involving people).
What is the immune system and what role does it have in biological therapy for cancer?
The immune system is a complex network of organs, tissues, and specialized cells. It recognizes and destroys foreign invaders, such as bacteria or viruses, as well as some damaged, diseased, or abnormal cells in the body, including cancer cells. An immune response is triggered when the immune system encounters a substance, called an antigen, it recognizes as
Professional societies do not recommend that children, even those with a family history suggestive of a BRCA1 or BRCA2 mutation, undergo genetic testing. This is because no risk-reduction strategies for children exist, and their risk of developing a cancer type associated with a BRCA1 or BRCA2 mutation is extremely low. After they become adults, however, they may want to obtain genetic counseling about whether or not to undergoing genetic testing.
Should people considering genetic testing for BRCA1 and BRCA2 mutations talk with a genetic counselor?
Genetic counseling is generally recommended before and after any genetic test for an inherited cancer syndrome. This counseling should be performed by a health care professional who is experienced in cancer genetics. Genetic counseling usually covers many aspects of the testing process, including:A hereditary cancer risk assessment based on an individual’s personal and family medical historyDiscussion of: The appropriateness of genetic testingThe medical implications of a positive or a negative test resultThe possibility that a test result might not be informative (see Question 12)The psychological risks and benefits of genetic test resultsThe risk of passing a mutation to childrenExplanation of the specific test(s) that might be used and the technical accuracy of the test(s)
How much does BRCA1 and BRCA2 mutation testing cost?
The cost for BRCA1 and BRCA2 mutation testing usually ranges from several hundred to several thousand dollars. Insurance policies vary with regard to whether or not the cost is covered. People considering BRCA1 and BRCA2 mutation testing may want to find out about their insurance coverage for genetic tests before having the test.
Some of the genetic testing companies that offer testing for BRCA1 and BRCA2 mutations may offer testing at no charge to patients who lack insurance and meet specific financial and medical criteria.
What does a positive BRCA1 or BRCA2 genetic test result mean?
BRCA1 and BRCA2 gene mutation testing can give several possible results: a positive result, a negative result, or an ambiguous or uncertain result.
A positive test result indicates that a person has inherited a known harmful mutation in BRCA1 or BRCA2 and, therefore, has an increased risk of developing certain cancers. However, a positive test result cannot tell whether an individual will actually develop cancer or when. Many women who inherit a harmful BRCA1 or BRCA2 mutation will never develop breast or ovarian cancer.
A positive genetic test result may also have important health and social implications for family members (see Question 15), including future generations. Unlike most other medical tests, genetic tests can reveal information not only about the person being tested but also about that person’s relatives:Both men and women who inherit harmful BRCA1 or BRCA2 mutations, whether or not they develop cancer themselves, may pass the mutations on to their sons and daughters. Each child has a 50 percent chance of inheriting a parent’s mutation.If a person learns that he or she has inherited a harmful BRCA1 or BRCA2 mutation, this will mean that each of his or her siblings has a 50 percent chance of having inherited the mutation as well.
What does a negative BRCA1 or BRCA2 test result mean?
A negative test result can be more difficult to understand than a positive result because what the result means depends in part on an individual’s family history of cancer.
If a close (first- or second-degree) relative of the tested person is known to carry a harmful BRCA1 or BRCA2 mutation, a negative test result is clear: it means that person does not carry the harmful mutation and cannot pass it on to their children. Such a test result is called a
In the National Cancer Act of 1971, NCI was given the authority to prepare and submit an additional annual budget proposal directly to the President for review and transmittal to Congress. This authority is unique to NCI, and the budget proposal created in response to it is often referred to as the
H. pylori is thought to spread through contaminated food and water and through direct mouth-to-mouth contact. In most populations, the bacterium is first acquired during childhood. Infection is more likely in children living in poverty, in crowded conditions, and in areas with poor sanitation.
What is gastric cancer?
Gastric cancer, or cancer of the stomach, was once considered a single entity. Now, scientists divide this cancer into two main classes: gastric cardia cancer (cancer of the top inch of the stomach, where it meets the esophagus) and non-cardia gastric cancer (cancer in all other areas of the stomach).
According to NCI’s Surveillance, Epidemiology, and End Results (SEER) Program, an estimated 21,600 people in the United States will be diagnosed with gastric cancer and 10,990 people will die of this cancer during 2013. Gastric cancer is the second most common cause of cancer-related deaths in the world, killing approximately 738,000 people in 2008 (3). Gastric cancer is less common in the United States and other Western countries than in countries in Asia and South America.
Overall gastric cancer incidence is decreasing. However, this decline is mainly in the rates of non-cardia gastric cancer (4). Gastric cardia cancer, which was once very uncommon, has risen in incidence in recent decades (5).
Infection with H. pylori is the primary identified cause of gastric cancer. Other risk factors for gastric cancer include chronic gastritis; older age; male sex; a diet high in salted, smoked, or poorly preserved foods and low in fruits and vegetables; tobacco smoking; pernicious anemia; a history of stomach surgery for benign conditions; and a family history of stomach cancer (6, 7).
H. pylori has different associations with the two main classes of gastric cancer. Whereas people infected with H. pylori have an increased risk of non-cardia gastric cancer, their risk of gastric cardia cancer is not increased and may even be decreased.
What evidence shows that H. pylori infection causes non-cardia gastric cancer?
Epidemiologic studies have shown that individuals infected with H. pylori have an increased risk of gastric adenocarcinoma (1,2,8