Primary prevention of ovarian cancer.

Ovarian cancer remains the deadliest gynecologic malignancy in the United States, killing more women each year than cervical and endometrial cancers combined. Despite aggressive operations and intensive chemotherapy, the 5-year survival rate is less than 40%. 1 Complications such as bowel obstruction, inanition, ascites, and pleural effusions can make this a wretched way to die. Hence, the finding of Hankinson et al 2 in this issue of JAMA is heartening: tubal sterilization may protect against this malignancy. See also p 2813. The Nurses' Health Study is not the first to observe this protection. 3-5 The importance of this research, however, stems from its design: a large, prospective cohort study. Cohort studies avoid some of the vexing problems of case-control studies, such as selection of an appropriate control group. Ascertainment bias is unlikely to have accounted for these results. The respondents were knowledgeable health professionals, and medical records confirmed reported illness. While