Fortner RT, et al. - Whether risk factor profiles in ovarian cancer may impact tumor aggressiveness, defined by time between diagnosis and death, independent of histology, was investigated in 4,584 invasive epithelial ovarian cancers identified from 21 prospective cohorts and classified as highly aggressive (death in <1 year, n=864), very aggressive (death in 1-<3 years, n=1,390), moderately aggressive (death in 3-<5 years, n=639), and less aggressive (lived 5+ years, n=1,691). Cox proportional hazards regression was used. An inverse association of a first/single pregnancy, vs nulliparity, with highly aggressive disease was observed, however, no association was observed for subsequent pregnancies. In contrast, similar associations with less aggressive disease were reported for first and subsequent pregnancies. Family history of ovarian cancer was only related to risk of less aggressive disease. Increased risk of highly aggressive disease was reported in association with high body mass index (≥35 vs 20-<25 kg/m²) and current smoking (vs never). Within histotypes, similar results were seen. Overall, findings were suggestive of a possible direct association of ovarian cancer risk factors with subtypes defined by tumor aggressiveness, rather than through differential effects on histology.