Tamoxifen OK'd But With Warning

Tamoxifen has become the first drug approved to help reduce the risk of breast cancer in women. The Food and Drug Administration has approved the prescription of the drug for women at high risk for developing the disease.

When it works, tamoxifen is a has been a extremely effective treatment.

"What we have actually seen is a true preventative effect" says Cleveland Clinic breast cancer specialist Dr. Holly Smedira. However she quickly adds that the drug has serious side effects, and that patients and their doctors should not view tamoxifen as the ultimate panacea.

She notes that tamoxifen "was associated with a doubling of uterine cancer" and a tripling of blood clotting in the legs and the lungs. Dr. Smedira says that some of the blood clotting cases were fatal, and adds that the drug has been linked to cataracts.

Acting FDA Commissioner Michael Friedman, a cancer specialist, said that "as valuable as tamoxifen is to some patients, the FDA strongly advises women and their doctors to carefully weigh the benefits and risks of tamoxifen before patients use the drug."

A study funded by the National Cancer Institute and announced last spring showed tamoxifen could cut the chances of developing breast cancer by 44 percent in women at high risk of the disease.

In medical terms, that's a significant cancer reduction. Approximately 6,600 American women who took tamoxifen for the study's 3-1/2 years had 69 fewer breast tumors than occurred in another 6,000 women who took a dummy pill.

Effects of long-term use are not known, the FDA cautioned. Nor does anyone know if breast cancer that appears in women who unsuccessfully tried tamoxifen will be more aggressive.

In studies so far, however, tamoxifen appeared mostly to reduce the smallest, easiest-to-treat cancers. And some smaller British studies have cast doubt on how effective the drug is.

The FDA ordered manufacturer Zeneca Inc., which sells tamoxifen under the brand name Zolvadex, to aggressively educate both doctors and women about just whose breast cancer risk is high enough to benefit from taking tamoxifen pills every day.