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Evidence is gradually accumulating on the best prophylactic options for women who carry mutations in the BRCA1 or BRCA2 gene. These women face a 60-80% lifetime risk of breast cancer and a 15-65% cumulative lifetime risk of ovarian cancer. In a prospective study, Kauff et al have compared the subsequent incidence of breast and ovarian cancer in 170 BRCA mutation carriers, over the age of 35, who chose to undergo either oophorectomy (removal of the ovaries) or surveillance for ovarian cancer [Kauff, N. et al (2002) N Engl J Med 346, 1609-1615 (Abstract)]. Of the 98 women who chose oophorectomy, one developed primary peritoneal cancer 16 months after surgery; of the 72 who chose surveillance, four were diagnosed with ovarian cancer and one with peritoneal cancer over the same period. Among those women who had not undergone prophylactic mastectomy, 3 out of 69 in the oophorectomy group developed breast cancer, compared with 8 out of 62 in the surveillance group. Combining the results for breast and ovarian cancer gave an overall hazard ratio of 0.25 for treatment by oophorectomy. Rebbeck et al report a retrospective study of 551 mutation carriers, of whom 259 opted for surveillance and 292 for oophorectomy [Rebbeck, T.R. et al (2002) N Engl J Med 346, 1616-1622 (Abstract)]. About 20% of the surveillance group developed ovarian cancer during 9 years of follow-up, compared with 1% of the oophorectomy group. These researchers also found the oophorectomy gave some protection against the development of breast cancer.

Comment: These two studies provide support for the current practice of advising BRCA mutation carriers – particularly carriers of mutations in BRCA1 – to reduce their risk of ovarian cancer by opting for oophorectomy once they have completed their family. Oophorectomy also appears to reduce the risk of subsequent breast cancer though less effectively than prophylactic mastectomy.