samedi 12 octobre 2013

Antioxidants and Cancer Prevention


What are antioxidants?

Antioxidants are chemicals that interact with and neutralize free radicals, thus preventing them from causing damage. Antioxidants are also known as

Cancer Staging

More information can be found in the NCI fact sheet Tumor Grade.

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

How To Find a Doctor or Treatment Facility If You Have Cancer

and are board certified as specialists. Doctors who are board eligible have obtained the required education and training but have not completed the specialty board examination.

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

Alcohol and Cancer Risk

the higher his or her risk of developing an alcohol-associated cancer. Based on data from 2009, an estimated 3.5 percent of all cancer deaths in the United States (about 19,500 deaths) were alcohol related (3).

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

Computed Tomography (CT) Scans and Cancer

to cause cancer. People should discuss the risks and benefits of CT with their doctors.

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

Biological Therapies for Cancer

do not target cancer cells directly. Other biological therapies, such as antibodies or segments of genetic material (RNA or DNA), do target cancer cells directly. Biological therapies that interfere with specific molecules involved in tumor growth and progression are also referred to as targeted therapies. (For more information, see Targeted Cancer Therapies.)

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