Tubal ligation, hysterectomy, and risk of ovarian cancer

To the Editor. —Dr Hankinson and colleagues 1 have reported that tubal ligation, and perhaps hysterectomy, may substantially reduce risk of ovarian cancer. How this risk reduction might be mediated is unknown, and various mechanisms have been proposed. There have been inconclusive reports on a posttubal sterilization syndrome, affecting blood supply, ovulation, steroid production by the ovaries, and menstrual regularity. Moreover, tubal sterilization might prevent contact of the ovary with fluid from the uterine cavity carrying carcinogens, such as talcum powder. In addition, the retrograde menstruation associated with intact fallopian tubes has been linked with salpingitis, endometriosis, and possibly systemic lupus erythematosus; thus, menstrual debris might be a carcinogen. 2 Another possible mechanism to consider is the antitumor action of general anesthetic agents. For example, one study of these agents demonstrated increased production of tumor necrosis factor during their administration, which was four to five times greater than in controls.