Bilateral Mastectomy Increased Among Young BRCA Carriers With Breast Cancer

Use of bilateral mastectomy increased substantially over 2 decades among young women with breast cancer and germline BRCA1 or BRCA2 pathogenic variants, according to an international retrospective cohort study published in JAMA Network Open. Geographic region and timing of genetic testing were strongly associated with surgical management.

The BRCA BCY Collaboration included 4,715 women aged 40 years or younger with unilateral stage I to III invasive breast cancer diagnosed from 2000 through 2020. Participants were treated at 109 centers across 5 continents. Median age at diagnosis was 35 years, and the analysis evaluated breast-conserving surgery, unilateral mastectomy, and bilateral mastectomy as primary surgical treatment.

Overall, 1,805 women (38.3%) underwent breast-conserving surgery, 1,752 (37.2%) underwent unilateral mastectomy, and 1,158 (24.6%) underwent bilateral mastectomy. Breast-conserving surgery decreased from 55.7% in 2000 to 27.0% in 2020, while bilateral mastectomy increased from 8.0% to 44.4%.

Bilateral mastectomy was performed in 57.0% of women tested before diagnosis, 38.5% of those tested within 6 months of diagnosis, and 5.1% of those tested later. Compared with testing after diagnosis, testing before diagnosis had an adjusted odds ratio (AOR) of 20.72 for bilateral mastectomy, while testing at diagnosis had an AOR of 6.83. Among women tested before or near diagnosis, rates ranged from 26.1% in Asia and Africa to 66.4% in North America.

The authors cautioned that the retrospective study lacked detailed information about surgical recommendations, shared decision-making, reconstruction access, and factors including insurance, family history, family planning, quality of life, cosmesis, and sexual functioning. The findings describe associations and treatment patterns rather than the relative merits of individual surgical options.

Source: Wong SM, Blondeaux E, Delucchi V, et al. Surgical management of early-onset breast cancer among young BRCA1 and BRCA2 carriers. JAMA Netw Open. 2026;9(8):e2630856. doi:10.1001/jamanetworkopen.2026.30856