Hormone replacement therapy and epithelial ovarian cancer: is there and association?

Recently it was estimated that about one-third of postmenopausal British women aged 50-64 years currently uses hormone replacement therapy (HRT) for treatment of climacteric symptoms and for other medical reasons. To reduce an excess risk of endometrial cancer induced by oestrogens, modern HRT regimens contain either sequential or continuous progestogens. The protective effect of parity and oral contraceptive use observed in the majority of epidemiological studies on epithelial ovarian cancer (EOC) suggest that hormonal factors are likely to operate in ovarian carcinogenesis. However, the studies where HRT was examined in relation to the risk of EOC have reported conflicting results. The objective of this epidemiological review is to evaluate the risk of EOC in relation to the use of HRT, with particular focus on the few studies where oestrogens and progestogens in HRT were assessed separately. Further, the findings regarding HRT and EOC risk will be discussed in the context of available aetiological hypotheses. Finally, any clinical implications are commented upon.