Comparing the effectiveness of bilateral mastectomy and surveillance in BRCA1 and BRCA2 mutation carriers

This study compared bilateral risk-reducing mastectomy and surveillance methods for reducing the risk of breast cancer in women with the BRCA1 or BRCA2 genetic mutations.

BRCA 1 and BRCA 2 are genetic mutations which increase the risk of breast cancer (BC). Women with these mutations can try to reduce their BC risk through regular surveillance, preventative chemotherapy, or bilateral risk-reducing mastectomy (BRRM), in which both breasts are removed to prevent the development of cancer. However, there is no clear evidence that shows whether BRRM really lowers the risk of BC beyond that of surveillance methods, whether it increases survival, or whether there is a difference in effectiveness depending on the type of mutation.  Surveillance can involve regular cancer screening using mammography or magnetic resonance imaging (MRI). These are imaging techniques that can detect cancer in an early stage.

This study included 570 women with the BRCA1 or BRCA2 mutation. 37% of women underwent BRRM (74% of these women had the BRCA1 mutation, 26% had BRCA2).  The remaining 63% of the women used surveillance methods, such as mammography and MRI.

Ten-year BC-free survival (10 year survival without development of BC) was 100% for BRRM and 74% for surveillance.  BC was diagnosed more often in women with the BRCA1 mutation (20%) versus the BRCA2 mutation (7%).  In women with the BRCA2 mutation, 100% of BCs were detected at an early stage, versus 72% in the BRCA1 women; the 4 women who developed metastatic BC all had the BRCA1 mutation.

In the BRRM group, some women (2.8%) were found to have BC that had not yet been diagnosed. Following BRRM, these women did not develop a recurrence of the disease. 

In summary, BRRM reduced BC risk in women with the BRCA1/2 mutation. BRRM was found to be an effective treatment for women with early-stage disease. Also, women with the BRCA1 mutation were more likely to develop BC than women with the BRCA2 mutation.

This study enrolled a significant number of participants, but long-term follow up of patients is needed to confirm that there was indeed a significant survival advantage in receiving BRRM.