A study, led by Steven A. Narod and Kelly Metcalfe from the Women’s College Research Institute in Toronto (Canada) has revealed that breast cancer patients carrying the BRCA1 gene who underwent oophorectomies were associated with a 62% reduction in death due to breast cancer. The results confirm previous study results of BRCA gene mutation carriers, which have reported reduced mortality associated with oophorectomy for women with a history of breast cancer.
It is well known that BRCA1 or BRCA2 germline mutations confer a lifelong breast cancer risk of up to 70%. Once women are diagnosed, they face high risks of both second primary breast and ovarian cancers.
Within the study, researchers sought to examine mortality and survival in 676 women with early-stage breast cancer who carried BRCA1 and BRCA2 gene mutations. Of the group, 345 women underwent oophorectomy after being diagnosed with breast cancer, whilse 331 women retained both ovaries.
The findings, published online by JAMA Oncology, reported that in the full group of 676 patients, 20-year survival was 77.4% and there was a 56% reduction in breast cancer death associated with oophorectomy, as well as a 65% reduction in all-cause mortality associated with oophorectomy.
Specifically, undergoing an oophorectomy was associated with a statistically significant reduction of 62% in breast cancer death in women carrying BRCA1 mutation; however there was not a significant reduction in women carrying a BRCA2 mutation. In the group of women who did not have oophorectomy, there were nine deaths.
Oophorectomies were performed, on average, 6 years after breast cancer diagnosis. However a subgroup of 70 BRCA1 carriers who underwent an oophorectomy within two years of their breast cancer diagnosis exhibited a 73% mortality reduction compared to BRCA1 carriers who did not undergo the operation. Thus, the findings indicate a potentially ‘protective’ effect of oophorectomy operations for delaying breast cancer deaths. The authors reported that this can be seen immediately after breast cancer diagnosis and persists for 15 years.
Mary L. Disiswrote in a related editor’s note: “The results provide a validation of the role of oophorectomy in conveying both a disease-free and overall survival benefit for BRCA1 mutation carriers. Oophorectomy after the primary diagnosis of breast cancer significantly reduced breast cancer-specific mortality in women with BRCA1 mutations but not in BRCA2 mutation carriers. In the entire group, oophorectomy was particularly effective for survival benefit in women with estrogen receptor-negative breast cancer.”
“The data reported here are compelling and suggest that the potential of oophorectomy should become part of the treatment discussion at the time of diagnosis for BRCA mutation carriers with early-stage breast cancers.”
Follow-up studies on women undergoing oophorectomy during initial treatment, particularly within the first year following diagnosis, as well as in BRCA2 carriers, will be warranted to confirm observations and further examine the protective effect of oophorectomies.
Sources: Metcalfe K, Lynch HT, Foulkes WD, et al. Effect of Oophorectomy on Survival After Breast Cancer in BRCA1 and BRCA2 Mutation Carriers. JAMA Oncology. DOI: 10.1001/jamaoncol.2015.0658 (2015); The JAMA Network press release