Bilateral mastectomy, once seen as a potential life-saving treatment for women with breast cancer and a BRCA1 pathogenic variant, may not provide any significant survival benefit, according to a recent international analysis. The study, presented at the San Antonio Breast Cancer Symposium by Kelly Metcalfe, RN, PhD, from the Women’s College Research Institute in Toronto, challenges the notion that bilateral mastectomy improves long-term survival rates in this specific patient population.
Metcalfe’s analysis compared the use of breast-conserving treatment (BCT) with unilateral mastectomy and bilateral mastectomy, evaluating their impact on breast cancer-specific survival over a 15-year period. The results indicated that the rates of breast cancer-specific survival were 86.2% for BCT, 78.7% for unilateral mastectomy, and 88.7% for bilateral mastectomy. However, when comparing the different treatment options, bilateral mastectomy was not significantly associated with a reduction in mortality (HR 0.83, P=0.52). Similarly, the hazard ratio for mortality in the unilateral mastectomy group versus BCT was 1.22 (95% CI 0.92-1.62), and 0.88 (95% CI 0.58-1.13) for the bilateral mastectomy group versus BCT.
Despite the lack of survival benefit, the study did find that women who underwent bilateral mastectomy were significantly less likely to be diagnosed with contralateral breast cancer during follow-up, compared to those who underwent BCT (0.8% vs. 10.8%) or unilateral mastectomy (11.4%). The reduced risk of contralateral breast cancer is a key consideration for patients with a BRCA1 pathogenic variant.
As germline genetic testing becomes increasingly integrated into clinical care for women with breast cancer, the importance of personalized treatment based on the patient’s genetic profile has gained significant attention. Metcalfe highlighted that around 3% to 4% of women with breast cancer carry a germline BRCA1 or BRCA2 mutation. Genetic test results allow physicians to tailor treatment plans for these individuals, taking into account the risks of both ipsilateral and contralateral breast cancers, as well as the high lifetime risk of ovarian cancer.
Dr. Brian Czerniecki from the Moffitt Cancer Center in Tampa, Florida offered his perspective on the findings. He stated that, despite the lack of survival benefit, he still recommends bilateral mastectomy for women with a BRCA1 pathogenic variant, especially younger patients who have a higher risk of developing a second cancer. The preventive aspect of bilateral mastectomy helps improve their life expectancy by reducing the chances of developing additional cancers. Furthermore, he highlighted that subsequent cancers in these patients are more likely to be triple-negative breast cancers (TNBC), which are notoriously harder to treat.
Metcalfe and her colleagues gathered data from medical records, including 2,482 women from 26 centers in 11 countries. Eligible participants had a diagnosis of stage I-III breast cancer and a documented BRCA1 pathogenic variant. The mean age at diagnosis was 43.1 years. Out of these patients, 34.3% underwent BCT, 46% underwent unilateral mastectomy, and 19.7% underwent bilateral mastectomy. The group that opted for bilateral mastectomy had a significantly younger mean age at diagnosis (41.3 years) compared to the other groups (43.5 years, P
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