Strategies for Cancer Prevention

As scientific evidence points to specific agents as the causes of cancer, cancer death rates might be reduced through avoidance of these factors. One such preventative action is to avoid smoking tobacco. In the case of certain viruses that are linked to cancer — for example, hepatitis B virus, which is linked to liver cancer — vaccination campaigns may reduce cancer incidence.

Certain modifications of diet — such as eating more fruits, vegetables, and legumes (e.g., peas and beans) and less red meat and saturated fats — can increase the odds of avoiding cancer. International epidemiological and laboratory studies provide strong evidence that a high intake of dietary fat is associated with an increased incidence of breast, colon, rectal, and prostate cancer.

Chemoprevention is the use of chemical compounds to intervene in the early precancerous stages of carcinogenesis (the development of cancer) and thereby reverse tumour formation. Many chemopreventive agents, both natural and synthetic, have been identified. Some of the most promising compounds are found in vegetables and fruits.

For example, dithiothiones are potential chemopreventive agents that naturally occur in broccoli and cauliflower. A number of anticancer drugs under study also show promise in preventing cancer. These include antiestrogen drugs such as tamoxifen, which has been shown to reduce the incidence of breast cancer.

Individuals with precancerous lesions and those with a previous cancer who are at risk for a second tumour are most often included in chemoprevention research trials.

It is possible to screen asymptomatic individuals for various types of cancer, such as breast, cervical, prostate, colorectal, and skin cancers. In these instances tests can detect a precancerous condition or a tumour in an early stage so that it can be removed. For example, self-examination of the breasts and yearly mammograms contribute significantly to the early detection of tumours and the success of therapy.

Self-exams are also useful in detecting early stages of testicular cancer. In other cases, however, such as when a detectable preclinical phase of a cancer is not known or there is no effective treatment for the cancer, screening programs may not be beneficial.