Prevention: Is it just the right drug away?

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An unwary world

In recent years, the Food and Drug Administration has approved two medications -- the cancer drug tamoxifen and the osteoporosis drug raloxifene -- for certain women at high risk of breast cancer. In 1999, breast cancer activists greeted tamoxifen, the first to be approved, with deep distrust because it was found to increase the risk of blood clots, uterine abnormalities and cataracts in post-menopausal women.

A year ago, the FDA approved the second, raloxifene, for breast cancer prevention in post-menopausal women at high risk for breast cancer. The agency concluded that the drug could cut the rate of breast cancer in such women by 44% to 71%, with side effect risks far lower than tamoxifen.

However, patients may not receive that message. In advertising raloxifene directly to consumers, the maker of the drug -- Eli Lilly and Co. -- scarcely mentions the cancer prevention effects, choosing to market the drug primarily for prevention of osteoporosis.

The result, Vogel says, is that most women at high risk of developing breast cancer who could benefit from drugs such as tamoxifen and raloxifene have never heard of these options.

"We're trying to find better, safer drugs all the time and trying to overcome both public and physician ignorance about this," Vogel says. "But you cannot imagine how many people I have to convince."

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Search far and wide

The federal government's comprehensive record of clinical trials (www.clinicaltrials .gov) lists 9,161 studies for pharmacological treatment of cancer in the United States but just 155 for cancer chemoprevention. And several of those 155 have been suspended.

Still, the number and diversity of agents under investigation for prevention is impressive. Researchers are exploring the use of arthritis, diabetes and asthma drugs for protection against lung cancers; a low dose of the cancer chemotherapy drug finasteride to suppress the development of prostate cancer; and drugs that include celecoxib, aspirin and other arthritis medications as well as common antibiotics to prevent the development of cancers of the colon and digestive tract.

An African sleeping-sickness drug called eflornithine, marketed as a drug to block unwanted hair growth, is thought to be promising in the prevention of a wide range of cancers, including those of the skin, esophagus, colon, prostate and cervix.