Preventive oophorectomy in BRCA mutation carriers reduced cancer risk by 80%
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BRCA1 or BRCA2 mutation carriers who underwent oophorectomy demonstrated an 80% reduced risk for ovarian, fallopian tube or peritoneal cancers, and a 77% reduced risk for all-cause mortality, according to study results.
Steven Narod, MD, professor of medicine at the University of Toronto, and colleagues used an international registry to identify 5,783 women who harbored a BRCA1 or BRCA2 mutation. All participants completed questionnaires at baseline and at least once during follow-up.
During a median follow-up of 5.6 years, there were 186 new incidences of ovarian, fallopian tube or peritoneal cancers, which resulted in 68 deaths. Of the 186 cases, 108 (58%) occurred in women who had not undergone oophorectomy (BRCA1, n=98; BRCA2, n=10).
The highest annual cancer risk for BRCA1 carriers occurred from age 50 to 59 years (1.7%), whereas the highest annual risk for BRCA2 carriers occurred from age 60 to 69 years (0.6%).
The incidence of occult carcinomas was 1.5% among women harboring BRCA1 mutations who underwent oophorectomy when younger than 40 years. The incidence increased to 3.8% among women who underwent oophorectomy from age 40 to 49 years.
Researchers estimated a 4% risk for ovarian cancer associated with delaying surgery among BRCA1 mutation carriers until age 40 years, and a 14.2% risk when delaying surgery until age 50 years.
Overall, bilateral oophorectomy was associated with an 80% reduction in the risk for ovarian, fallopian or peritoneal cancers (HR=0.2; 95% CI, 0.13-0.3).
Researchers then estimated oophorectomy’s effect on mortality up to age 70 years. They calculated a 0.23 HR (95% CI, 0.13-0.39) for all-cause mortality among women without a history of cancer at baseline.
“These data are so striking that we believe prophylactic oophorectomy by age 35 should become a universal standard for women with BRCA1 mutations,” Narod said in a press release. “Women with BRCA2 mutations, on the other hand, can safely delay surgery until their 40s, since their ovarian cancer risk is not as strong.”
Disclosure: The researchers report no relevant financial disclosures.