Hormone replacement therapy and the risk of epithelial ovarian carcinoma: a meta-analysis.

OBJECTIVE To determine if use of postmenopausal hormone replacement therapy (HRT) increases the risk of invasive epithelial ovarian carcinoma. DATA SOURCES English-language articles published from January 1966 to June 1997 examining HRT and ovarian cancer were found by using MEDLINE, searching the bibliographies of relevant articles and by consulting experts. STUDY SELECTION Of 327 articles identified, nine provided data on the risk of invasive cancer among ever-users of HRT and were selected for inclusion by consensus of two independent reviewers. Studies were included if cases were age-matched to controls or results were age-adjusted and if women with bilateral salpingo-oophorectomy were excluded. TABULATION, INTEGRATION, AND RESULTS Two independent unblinded reviewers abstracted data regarding risk of developing epithelial ovarian carcinoma and use of HRT. A general variance-based, fixed-effects model was used to calculate summary relative risks. Ever-use of HRT was associated with an increased risk of developing invasive epithelial ovarian carcinoma (odds ratio [OR] 1.15; 95% confidence interval [CI] 1.05, 1.27). Use of HRT for more than 10 years was associated with the greatest risk of ovarian cancer (OR 1.27; 95% CI 1.00, 1.61). CONCLUSION Prolonged use of hormone therapy by postmenopausal women may be associated with an increased risk of developing epithelial carcinoma of the ovary.