Ovarian cancer, ovulation and side of origin.

Reports of more right-sided ovarian cancers and more ovulations in the right ovary seemed to offer powerful support for the theory that ovulation, per se, leads to ovarian cancer risk. We examined laterality in 25,692 epithelial ovarian cancers diagnosed in 1973-89 included in the US Surveillance, Epidemiology, and End Results system of cancer registries. Ovarian cancer occurred equally often in the left and right ovaries in this large series of incident cases.