Reserpine and breast cancer.

After a series of studies on the linkage of reserpine with breast cancer, both evidence and interpretation appeared to be in conflict. Our case-control survey of long-term, comprehensive records from the Kaiser Foundation Medical Care Program, on 108 hypertensive breast cancer cases and 324 hypertensive controls, matched by year of birth and by race, produces a significant positive association between reserpine use and breast cancer. However, the association vanishes upon further matching with respect to the year of the first hypertension diagnosis and the subsequent length of follow-up. We thus fail to support suspicions of causality.