Reducing breast cancer risk 31/5/02. By the Public Health Genetics Unit Two studies find that removal of the ovaries reduces cancer risk in BRCA mutation carriers.

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 per cent lifetime risk of breast cancer and a 15-65 per cent 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.

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. About 20 per cent of the surveillance group developed ovarian cancer during 9 years of follow-up, compared with 1 per cent of the oophorectomy group. These researchers also found the oophorectomy gave some protection against the development of breast cancer.

PHGU 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.

Article courtesy of the Public Health Genetics Unit .

Further reading

Kauff N et al. Risk-reducing salpingo-oophorectomy in women with a BRCA1 or BRCA2 mutation. N Engl J Med 2002 346: 1609-1615. Abstract

Rebbeck TR et al. Prophylactic oophorectomy in carriers of BRCA1 or BRCA2 mutations. N Engl J Med 2002346: 1616-1622. Abstract