American Society of Breast Surgeons’ Practice Patterns After Publication of the SSO-ASTRO-ASCO DCIS Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation

Abstract

The SSO-ASTRO-ASCO consensus guideline on margins for breast-conserving surgery with whole breast irradiation in ductal carcinoma in situ (DCIS) recommended a 2-mm margin. We sought to determine the impact of guideline publication on clinician practice. A total of 3081 members of the American Society of Breast Surgeons (ASBrS) received a survey. Respondents' clinical practice type and duration, guideline familiarity, and margin width preferences before and after publication were assessed. Clinical practice pattern differences before and after publication were investigated using McNemar's test. A total of 767 (24.9%) of those surveyed responded. Most (92.4%) indicated guideline familiarity. Of those familiar, re-excision preference for DCIS and a positive margin remained the same before (94.4%) and after (94.3%) publication (McNemar's test p = 1.0). Following publication, surgeons were more likely to avoid re-excision to achieve margins wider than 2-mm (82.3% pre versus 87.5% post, p = 0.002). More surgeons performed re-excision for a close margin with pure DCIS (25.9% pre versus 36.5% post, p < 0.001) and with DCIS with microinvasion (DCIS-M) (40.7% pre versus 52.3% post, p < 0.001). For patients with invasive disease with extensive intraductal component (EIC) and a close margin, preference to avoid re-excision was similar (51.2% per versus 55.2% post, p = 0.071). Since guideline publication, surgeons are less likely to perform re-excision to obtain a margin greater than 2-mm and more likely to perform re-excision to obtain a 2-mm margin for both pure DCIS and DCIS-M. Preference to avoid re-excision with a close margin and EIC was similar before and after publication.