Effect of the Ductal Carcinoma In Situ Margin Consensus Guideline Implementation on Re-Excision Rates, Satisfaction, and Cost.

ABSTRACT

INTRODUCTION: The 2016 consensus guideline on margins for breast-conserving surgery (BCS) with whole-breast irradiation (WBI) for ductal carcinoma in situ (DCIS) recommended 2 mm margins to decrease local recurrence rates. We examined re-excision rates, cost, and patient satisfaction before and after guideline implementation. METHODS: From an Institutional Review Board-approved database, patients with DCIS who underwent BCS with over 1 year of follow-up at one academic institution and one community cancer center were evaluated. Two groups were compared based on when they received treatment, i.e. before (pre-consensus [PRE]) and after November 2016 (post consensus [POST]), with respect to outcome and cost parameters. RESULTS: After consensus guideline implementation, re-excision rate (32.1% vs. 20.0%) and mastectomy conversion (8.3% vs. 2.3%) significantly increased, although total resection volume, operative cost per patient, and satisfaction with breast scores did not differ. Not all patients with <2 mm margins were re-excised, although the re-excision rate among this subset significantly increased (62.4% vs. 31.3%). On multivariable analysis controlling for age, estrogen receptor status, WBI use, and margin status, surgery after consensus guideline publication was independently associated with a higher re-excision rate (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.08-3.59, p = 0.03) and a higher rate of conversion to mastectomy (OR 6.84, 95% CI 1.67-28.00, p = 0.007). CONCLUSIONS: Implementation of the 2016 margin consensus guideline for DCIS resulted in an increase in re-excisions and mastectomy conversions at two institutions. Research is needed for operative tools and strategies to decrease DCIS re-excision rates.