Hormone replacement therapy and the risk of invasive epithelial ovarian cancer in Swedish women. J Natl Cancer Inst 2002;94:497–504

mainly used to relieve climacteric symptoms, increases a woman’s risk for uterine endometrial cancer and epithelial ovarian cancer (EOC). Estrogens are often combined with progestins in hormone replacement therapy (HRT) to re-duce the risk of uterine endometrial cancer. Data on the association between HRT including progestins and EOC risk are limited. This nationwide case–control study examined EOC risk in relation to HRT regimens with sequentially added progestins (HRTsp) and continuously added proges-tins (HRTcp). Methods: Between 1993 and 1995, we enrolled 655 histologically verified incident case patients with EOC and 3899 randomly selected population controls, all 50–74 years of age. Data on HRT use were collected through mailed questionnaires. Multivariate-adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated by the use o