Are pesticides, electric power lines or other, unknown environmental factors leading to an increase in cancer rates? Recent studies from the American Council on Science and Health (ACSH) and the National Cancer Institute (NCI) conclude that the answer is "no."

In fact, for the past 40 years, the incidence of most forms of cancer has remained constant or even decreased - with lung cancer and AIDS-related cancers being the exceptions. The appearance of rising cancer rates is explained in large part by better testing methods.

According to the ACSH report, improved cancer-screening methods have created an impression of higher incidence of cancer. For example:

• In 1980, the breast cancer rate for women was reported as 85.2 per 100,000.

• In 1987, it rose to 112.4 per 100,000, then declined the next two years.

• The higher rates were due to increased detection of cancer through use of mammography and other screening methods, rather than an actual change in the incidence of cancer.

The NCI study attributes much of the increase in reported breast and prostate cancer rates not just to better screening techniques, but also to more frequent use of such diagnostic tests.

Both studies conclude that for people under 55, the mortality rates for most cancers are actually declining.

The studies agree that most cancers are related to known lifestyle factors: tobacco and alcohol abuse, diet, radiation, sexually transmitted diseases and exposure to sunlight.

Source: Brian J. Taylor, "Cancerous Myths," Reason, January 1996, Reason Foundation, 3415 S. Sepulveda Boulevard, Suite 400, Los Angeles, CA 90034, (310) 391-2245.