Anticipated Versus Unanticipated Incomplete Mohs Micrographic Surgery for Keratinocyte Carcinomas: Impact on Treatment Delays and Final Margin Status.

Abstract

Mohs micrographic surgery may be discontinued with positive margins as an anticipated strategy for multidisciplinary care or as an unanticipated occurrence. Management of primary tumors has not been compared after anticipated versus unanticipated incomplete Mohs micrographic surgery (iMMS). To compare rates and timing of adjuvant surgery after iMMS and final margin status when iMMS is anticipated versus unanticipated. Secondary outcomes were preoperative and intraoperative clinicopathologic factors associated with iMMS. Cases of iMMS of keratinocyte carcinomas at a tertiary academic center between 2005 and 2022 were classified as anticipated (preoperative assembly of multidisciplinary teams) or unanticipated (ad hoc management of positive margins). Rate, timing, and final margin status of adjuvant surgery was compared between anticipated and unanticipated iMMS cohorts using χ2/Fisher exact test for categorical variables and t-test for continuous variables. Of 127 iMMS cases, 51.2% (65/127) were anticipated. Anticipated iMMS cases were more likely to undergo additional resection (98.5% vs 72.6%, p < .001), with fewer delays (3.9 vs 13.2 days, p < .001) and higher rates of final margin clearance (84.6% vs 59.7%, p < .001). When iMMS is anticipated as part of multidisciplinary care, patients are more likely to undergo additional resection, with fewer delays to next surgery and higher final margin clearance rates.