Reproduction-related risk factors for mucinous and nonmucinous epithelial ovarian cancer

The proposition that mucinous ovarian cancer has an etiology distinct from that of other histologic types has been evaluated using data from a populat ion-based case-control study of epithelial ovarian cancer conducted in 1990 -1993 among Australian women aged 18-79 years. The protective effects of pa rity and oral contraceptive use were greater in nonmucinous than in mucinou s ovarian tumors. However, these differences appeared to be driven largely by the effect of ovulatory life, which was positively associated with nonmu cinous tumors only. An association with family history of breast and/or ova rian cancer also appeared to be restricted to nonmucinous cancers. These re sults lend support to the hypothesis that mucinous and nonmucinous ovarian tumors develop via different causal mechanisms.