Cancer Prevention Health Article

Definition

Preventing the incidence of cancer is complex and involves many factors which ultimately work by avoiding or limiting exposure to carcinogens. Known carcinogens in humans include physical, chemical, viral, and bacterial carcinogens. Physical carcinogens include the hydrocarbon byproducts of cigarette smoke, radiation, and asbestos. Benzene and vinyl chloride are examples of chemical carcinogens. The human papillomaviruses, which play a role in the development of cervical cancer, are viral carcinogens. A bacterial carcinogen is the bacteria, Helicobacter pylori, which has been linked to the cancer B-cell lymphoma, unique to the gastric mucosa. Familial (hereditary) carcinogenesis plays a role in as many as 15% of all human cancers and has been implicated as the cause of some cases of melanoma, breast, colon, and other cancers.

Some factors that place individuals at high risk for the development of cancer can be modified to decrease risk for development. For example, lifestyle and environmental changes can be made to decrease risk. Behavior modification such as dietary changes, exercise, and avoiding exposure to known carcinogens are primary prevention measures that everyone should adopt.

An evolving field, chemoprevention, is the use of vitamins or medicines to prevent cancer development. Chemopreventive agents have the ability to potentially delay and even reverse the sequence of events at the cellular level that change a normal cell to a cancer cell. An example of a chemopreventive agent is tamoxifen, a drug that is effective in preventing breast cancer in women who are at high risk for the development of breast cancer. Vaccines for Hepatitis B virus will not only prevent primary Hepatitis B and liver failure, but also liver cancer.

Preventive surgery may be an option for those individuals who are considered to be at very high risk of developing cancer because of a genetic or inherited predisposition. Examples of preventive surgery are prophylactic mastectomy to reduce risk for breast cancer, and colon polyp removal in individuals at high risk for the development of colon cancer.

In 1999 the American Cancer Society (ACS) estimated that 173, 000 cancer deaths were caused by cigarette smoking, and an additional 20, 000 cancer deaths were due to excessive alcohol consumption. All cancers caused by smoking cigarettes and by excessive use of alcohol can be completely prevented. According to the ACS, up to one-third of the more than 550, 000 cancer deaths expected to occur in the United States in 2001 are related to poor nutrition or insufficient physical exercise. Many of the more than one million skin cancers which develop annually could be prevented by adopting protective measures from ultraviolet radiation caused by the sun.

Different cancers are associated with different risk factors. While modification of risk factors plays an important role in the prevention of cancer, it is known that some individuals who have one or more risk factors never develop cancer. Others, however, who have no known risk factors, are eventually diagnosed with cancer. Research aimed at identifying additional risk factors for specific cancers continues.