A multicentre study of rauwolfia derivates and breast cancer

Abstract

Studies reporting a suspected association between breast cancer and rauwolfia derivatives were first published in 1974 and more recent studies have produced conflicting results. A further study is described in which groups of investigators from Aberdeen, Dundee and London attempted to ascertain the previous exposure to rauwolfia derivatives of female patients discharged from hospital with a confirmed diagnosis of breast cancer. Their exposure as recorded in the hospital and general practitioners' records was compared with that in two control groups, matched by general practitioner, age, year of admission to hospital and marital state, the first comprising patients with a cancer other than breast cancer and the second, patients with a non-malignant disorder. For patients with breast cancer compared with those with a non-malignant disorder the overall estimate of the relative risk of breast cancer in patients exposed to rauwolfia derivatives is 0.94 (95 patients exposed). The occurrence of hypertension and use of hypotensive agents and prolactin stimulators was also noted. Possible sources of bias were examined and none appeared to be significant. The problems created by the multicentre approach are also discussed.