Higher Stage of Disease Is Associated With Bilateral Mastectomy Among Patients With Breast Cancer: A Population-Based Survey.

Background: The reasons for increasing rates of bilateral mastectomy for unilateral breast cancer are incompletely understood, and associations of disease stage with bilateral surgery have been inconsistent. We examined associations of clinical and sociodemographic factors, including stage, with surgery type and reconstruction receipt among women with breast cancer.

Patients And Methods: We surveyed a diverse population-based sample of women from Northern California cancer registries with stage 0 to III breast cancer diagnosed during 2010-2011 (participation rate, 68.5%). Using multinomial logistic regression, we examined factors associated with bilateral and unilateral mastectomy (vs. breast-conserving surgery), adjusting for tumor and sociodemographic characteristics. In a second model, we examined factors associated with reconstruction for mastectomy-treated patients.

Results: Among 487 participants, 58% had breast-conserving surgery, 32% had unilateral mastectomy, and 10% underwent bilateral mastectomy. In adjusted analyses, women with stage III (vs. stage 0) cancers had higher odds of bilateral mastectomy (odds ratio [OR], 8.28; 95% confidence interval, 2.32-29.50); women with stage II and III (vs. stage 0) disease had higher odds of unilateral mastectomy. Higher (vs. lower) income was also associated with bilateral mastectomy, while age ≥ 60 years (vs. < 50 years) was associated with lower odds of bilateral surgery. Among mastectomy-treated patients (n = 206), bilateral mastectomy, unmarried status, and higher education and income were all associated with reconstruction (P < .05).

Conclusion: In this population-based cohort, women with the greatest risk of distant recurrence were most likely to undergo bilateral mastectomy despite a lack of clear medical benefit, raising concern for overtreatment. Our findings highlight the need for interventions to assure women are making informed surgical decisions.