Rauwolfia derivatives and breast cancer.

During the course of a collaborative study initiated in investigate the relationship of breast cancer and the use of hormones, it was possible to study the possible relationship of rauwolfia derivatives, mainly reserpine, to breast cancer. Interviews were administered to breast cancer patients admitted to five hospitals in the Baltimore metropolitan area. The study of reserpine use was conducted for a period of approximately one and a half years and information on reserpine use was obtained on 164 breast cancer cases. Each case was matched with a control with respect to age, color, hospital of admission, and admission date. An additional set of controls was drawn from women residing in the same neighborhood as the cases. Neither reserpine, methyldopa, nor thiazides were found to be significantly associated with breast cancer. The exclusion from the analysis of hospital controls with a diagnosis of hypertensive disease and their matched cases did not significantly alter the results. Those cases who used reserpine, used more for longer periods of time than did the controls, however this was judged inconclusive due to a considerable amount of missing data. After comparison of these results with previously reported studies, it did not appear that reserpine was strongly associated with breast cancer. However, because of methodological problems and differences between the studies, a possible small overall relationship could not be definitely excluded.