After Cancer

Of the 120,000 new cases of breast cancer diagnosed annually in the U.S., as many as 90,000 occur in women who are postmenopausal or over 50. In roughly half of these older women, the malignant cells have spread to nearby lymph nodes; some 30% die of recurring cancer within five years after surgery. That grim toll may soon be reduced. A National Institutes of Health advisory panel last week recommended the postsurgery use of a drug called tamoxifen in most of these cases, saying that it could cut the death rate by 20%.

Tamoxifen's effectiveness stems from the fact that the proliferation of breast-cancer cells in two-thirds of older women seems dependent on estrogen, the female sex hormone. The drug acts by blocking receptors for estrogen on the surfaces of cells that have migrated from the breast tumor, thus halting the division of the cells and preventing them from seeding tumors in other parts of the body. Unlike conventional chemotherapy, which usually causes loss of hair and severe nausea, tamoxifen produces only minor side effects, such as hot flashes and mild nausea, and only in about one-quarter of patients.

Still, the drug is not a cure-all. The NIH panel reported that it is ineffective against breast-cancer cells that are not estrogen dependent and seems to have little effect in premenopausal women, who respond best to a combination of chemotherapy drugs. The panel stressed that most older breast- cancer victims whose lymph nodes have not been invaded by malignant cells need neither tamoxifen nor chemotherapy after surgery, but urged that they have frequent checkups.