Breast cancer remains a significant health concern for women globally, and advancements in treatment options have led to more personalized approaches based on individual patient characteristics. One such approach is the use of bilateral mastectomy, particularly in women with a pathogenic BRCA1 variant. However, a recent international analysis has questioned the survival benefits of this aggressive treatment option.
The study, presented by Kelly Metcalfe, RN, PhD, from the Women’s College Research Institute in Toronto, aimed to evaluate the impact of bilateral mastectomy on survival rates in women with breast cancer and a documented BRCA1 pathogenic variant. The results indicated that bilateral mastectomy did not significantly improve mortality rates (HR 0.83, P=0.52) when compared to breast-conserving treatment (BCT).
The 15-year breast cancer-specific survival rates were 86.2% for BCT, 78.7% for unilateral mastectomy, and 88.7% for bilateral mastectomy. However, on multivariate analysis, the risk of mortality in the unilateral mastectomy group was only slightly higher compared to the BCT group (HR 1.22, 95% CI 0.92-1.62). Similarly, the risk of mortality in the bilateral mastectomy group did not significantly differ from the BCT group (HR 0.88, 95% CI 0.58-1.13).
Despite the lack of survival benefits, women who underwent bilateral mastectomy experienced significantly lower rates of contralateral breast cancer development during follow-up. Only 0.8% of women in the bilateral mastectomy group developed contralateral breast cancer, compared to 10.8% in the BCT group and 11.4% in the unilateral mastectomy group (P<0.0001). This suggests that bilateral mastectomy may be effective in reducing the risk of developing secondary breast cancer.
Genetic testing has become an integral part of clinical care for women with breast cancer, particularly those with a family history or suspected BRCA1/BRCA2 mutations. The results of these genetic tests allow for personalized treatment approaches. According to Metcalfe, the treatment decision for these patients involves not only targeting the primary cancer but also considering their increased risk of developing both ipsilateral and contralateral breast cancer, as well as a high lifetime risk of ovarian cancer.
Dr. Brian Czerniecki from the Moffitt Cancer Center in Florida maintains that bilateral mastectomy remains a valid recommendation, especially for younger patients with a BRCA1 pathogenic variant. The high risk of developing a second cancer justifies this aggressive approach, as preventing a secondary cancer can contribute to improved life expectancy. Additionally, any subsequent cancers are more likely to be triple-negative breast cancers (TNBC), which are notoriously difficult to treat.
The study analyzed data from 2,482 women across 26 centers in 11 countries. All 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. Of the participants, 34.3% underwent BCT, 46% underwent unilateral mastectomy, and 19.7% underwent bilateral mastectomy.
While bilateral mastectomy did not demonstrate a significant survival advantage in this study, it remains an important treatment option for women with breast cancer and a pathogenic BRCA1 variant. However, the decision to pursue bilateral mastectomy should be based on careful consideration of each patient’s individual risk factors, preferences, and priorities. Continued research in this field, including exploring the potential benefits of newer treatments like olaparib and the protective effects of oophorectomy, is essential to refine treatment strategies and improve patient outcomes.
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