Is a 0.2% chance of death from breast cancer worth a bilateral prophylactic mastectomy?

That's the choice women with one or more breast cancer risk factors have to make, according to the results of a recent retrospective case-cohort study of women aged 18 to 80.

Researchers studied 276 women who received bilateral prophylactic mastectomy and a random sample of 196 women representing an underlying cohort of 666,800 women with elevated breast cancer risk but no mastectomy. Breast cancer risk factors consisted of a family history of the disease, a history of atypical hyperplasia, and one or more breast biopsies with benign findings.

Breast cancer developed in one woman (0.4%) after bilateral breast removal and in 26,800 women (4.0%) who did not opt for the prophylactic procedure, making the hazard ratio for breast cancer occurrence after bilateral mastectomy 0.005 (95% CI, 0.001–0.044). None of the women who elected to have the procedure died of breast cancer, while 0.2% of those who did not have a mastectomy died of the disease.