Reasons for re-excision after lumpectomy for breast cancer: insight from the American Society of Breast Surgeons Mastery(SM) database.

BACKGROUND: There is marked variability of re-excision rates after initial lumpectomy for breast cancer. Reasons for re-excision and variability across surgeons have not been well documented. We hypothesized the American Society of Breast Surgeons (ASBrS) Mastery(SM) Program can identify reasons for re-excision.
METHODS: Data from January 1 to 7 November 2013 were evaluated in the ASBrS Mastery(SM) Program to determine re-excision lumpectomy rate (RELR). On 1 June 2013, a tool to track reasons for re-excision was developed. Variation in re-excision rate by surgeon and patient characteristics was performed by Chi square test and Fisher's test for univariate analysis, then logistic regression with backwards elimination method for multivariate analysis.
RESULTS: For 6,725 patients undergoing initial lumpectomy for cancer, 328 surgeons reported 1,451 (21.6 %) patients had one or more re-excisions. The most common reasons for re-excision were ink positive margins in 783 (49.7 %), margin <1 mm (34.3 %), and margin 1-2 mm (7.2 %). By multivariate analysis, re-excision rates were lower in patients aged less than 35 years, with White (non-) Hispanic ethnicity, and, among surgeons in solo practice, more years in practice and higher-volume practice.
CONCLUSION: Half of re-excisions after initial lumpectomy were performed for margins that are positive. Most of the remainder were for negative close (<1-2 mm) margins. This information corroborates surgeon survey data regarding reasons for re-excision and provides proof of concept the Mastery(SM) Program can capture surgical outcome data in real time, providing opportunity and a method for future performance improvement.