Nationwide trends in mastectomy for early-stage breast cancer.

IMPORTANCE Accredited breast centers in the United States are measured on performance of breast conservation surgery (BCS) in the majority of women with early-stage breast cancer. Prior research in regional and limited national cohorts suggests a recent shift toward increasing performance of mastectomy in patients eligible for BCS. OBJECTIVE To examine whether mastectomy rates in patients eligible for BCS are increasing over time nationwide, and are associated with coincident increases in breast reconstruction and bilateral mastectomy for unilateral disease. DESIGN, SETTING, AND PARTICIPANTS We performed a retrospective cohort study of temporal trends in performance of mastectomy for early-stage breast cancer using multivariable logistic regression modeling to adjust for pertinent covariates and interactions. We studied more than 1.2 million adult women treated at centers accredited by the American Cancer Society and the American College of Surgeons Commission on Cancer from January 1, 1998, to December 31, 2011, using the National Cancer Data Base. EXPOSURES Year of breast cancer diagnosis. MAIN OUTCOMES AND MEASURES Proportion of women with early-stage breast cancer who underwent mastectomy. Secondary outcome measures include temporal trends in breast reconstruction and bilateral mastectomy for unilateral disease. RESULTS A total of 35.5% of the study cohort underwent mastectomy. The adjusted odds of mastectomy in BCS-eligible women increased 34% during the most recent 8 years of the cohort, with an odds ratio of 1.34 (95% CI, 1.31-1.38) in 2011 relative to 2003. Rates of increase were greatest in women with clinically node-negative disease (odds ratio, 1.38; 95% CI, 1.34-1.41) and in situ disease (odds ratio, 2.05; 95% CI, 1.95-2.15). In women undergoing mastectomy, rates of breast reconstruction increased from 11.6% in 1998 to 36.4% in 2011 (P < .001 for trend). Rates of bilateral mastectomy for unilateral disease increased from 1.9% in 1998 to 11.2% in 2011 (P < .001). CONCLUSIONS AND RELEVANCE In the past decade, there have been marked trends toward higher proportions of BCS-eligible patients undergoing mastectomy, breast reconstruction, and bilateral mastectomy. The greatest increases are seen in women with node-negative and in situ disease. Mastectomy rates do not yet exceed current American Cancer Society/American College of Surgeons Commission on Cancer accreditation benchmarks. Further research is needed to understand factors associated with these trends and their implications for performance measurement in American Cancer Society/American College of Surgeons Commission on Cancer centers.