Contemporary Analysis of Reexcision and Conversion to Mastectomy Rates and Associated Healthcare Costs for Women Undergoing Breast-Conserving Surgery.

Purpose: This study was designed to provide a comprehensive and up-to-date understanding of population-level reoperation rates and incremental healthcare costs associated with reoperation for patients who underwent breast-conserving surgery (BCS).

Methods: This is a retrospective cohort study using Merative™ MarketScan commercial insurance data and Medicare 5% fee-for-service claims data. The study included females aged 18-64 years in the commercial cohort and females aged 18 years and older in the Medicare cohort, who underwent initial BCS for breast cancer in 2017-2019. Reoperation rates within a year of the initial BCS and overall 1-year healthcare costs stratified by reoperation status were measured.

Results: The commercial cohort included 17,129 women with a median age of 55 (interquartile range [IQR] 49-59) years, and the Medicare cohort included 6977 women with a median age of 73 (IQR 69-78) years. Overall reoperation rates were 21.1% (95% confidence interval [CI] 20.5-21.8%) for the commercial cohort and 14.9% (95% CI 14.1-15.7%) for the Medicare cohort. In both cohorts, reoperation rates decreased as age increased, and conversion to mastectomy was more prevalent among younger women in the commercial cohort. The mean healthcare costs during 1 year of follow-up from the initial BCS were $95,165 for the commercial cohort and $36,313 for the Medicare cohort. Reoperations were associated with 24% higher costs in both the commercial and Medicare cohorts, which translated into $21,607 and $8559 incremental costs, respectively.

Conclusions: The rates of reoperation after BCS have remained high and have contributed to increased healthcare costs. Continuing efforts to reduce reoperation need more attention.