Estrogen replacement therapy use and risk of ovarian cancer: results from two Italian studies and review of the literature

The association between hormone replacement therapy (HRT) use and risk of ovarian cancer has been the subject of much epidemiological debate, and published studies analyzing this association have shown controversial results. A re-analysis of data from 12 case-control studies, based on 2197 white women with invasive epithelial ovarian cancer, found a pooled RR of invasive ovarian cancer for ever-use of HRT of 0.9 in hospital-based and 1.1 in population-based studies, with no consistent duration-risk relationship. Some points are, however, still open to debate. It is unclear whether such a moderate increase in risk is present for all histologic subtypes of epithelial ovarian cancer, or whether it is limited to specific subgroups. In conclusion, the evidence for an association between HRT and ovarian cancer is less consistent than that for endometrial and breast cancers, and available data exclude any strong association between HRT and epithelial ovarian cancer, although a moderate positive association is possible.