Meta-analysis: preventive mastectomy linked to lower death rates in BRCA1/2 carriers compared with screening alone

Women who carry harmful variants in the BRCA1 or BRCA2 genes face a high lifetime risk of breast and ovarian cancer. They are usually offered intensive screening or preventive surgery — removal of the breasts (risk-reducing mastectomy, RRM) and/or of the ovaries and fallopian tubes (RRSO). A study in JAMA Network Open, published on 30 October 2026, asked whether mastectomy itself improves survival.

The study

• A network meta-analysis pooling 5 observational studies with 7,937 female patients carrying pathogenic BRCA1/2 variants.
• It compared RRM with breast-cancer screening by MRI or mammography, trying to separate the effect of mastectomy from that of RRSO.

Findings

• RRM was associated with a significant decrease in all-cause mortality compared with screening.
• The authors conclude that RRM may provide a survival benefit beyond that attributable to ovary removal and should remain a central part of individualised risk-reduction counselling.

Limitations

All included studies were observational, so women who chose surgery may differ from those who chose screening in ways that affect survival (age, health, access to care); only five studies were available; and network meta-analysis relies on indirect comparisons. This summary is based on the journal’s media release; detailed effect sizes were not given there. Preventive surgery is a major personal decision — carriers should discuss options with a genetic counsellor and their doctors.