Hormone replacement therapy and survival after surgery for ovarian cancer OBJECTIVE--To evaluate whether hormone replacement therapy affects survival in women who have undergone bilateral salphingo-oophorectomy because of epithelial ovarian cancer. DESIGN--Retrospective analysis by review of patients' notes and questionnaires completed by general practitioners to compare the overall survival and disease free survival in patients with ovarian cancer who did or did not receive hormone replacement therapy after diagnosis. Data were analysed by Cox regression, with hormone replacement therapy as a time dependent covariate because patients who received hormone replacement did so at different times after diagnosis. SETTING--Gynaecological oncology unit of Royal Marsden Hospital. PATIENTS--373 patients aged 50 years or younger who attended the hospital from 1972 to 1988. All of the women had undergone bilateral salpingoophorectomy for epithelial ovarian cancer. In all, 78 had received hormone replacement therapy, starting at a median of four months after diagnosis. INTERVENTION--A questionnaire was sent to the general practitioners of all patients who were not recorded as having received hormone replacement therapy. MAIN OUTCOME MEASURES--Overall survival and disease free survival. RESULTS--There was no significant difference in survival between women receiving hormone replacement therapy and those not receiving it after accounting for the effects of other known prognostic factors (stage of cancer, differentiation of tumour, histological results, and time to relapse). The relative risk of dying in those who received hormone replacement therapy was 0.73 (95% confidence interval 0.44 to 1.20). In addition, there was no significant difference in disease free survival (relative risk in those receiving hormone replacement therapy was 0.90; 95% confidence interval 0.52 to 1.54). CONCLUSIONS--This study shows that hormone replacement therapy is unlikely to have a detrimental effect on the prognosis of patients with ovarian cancer, but this would be shown conclusively only by a randomised controlled trial. 