Curettage Versus Topical Treatment for Positive Superficial Margins After Mohs Surgery

BACKGROUNDPositive margins of squamous cell carcinoma in situ or superficial basal cell carcinoma after Mohs micrographic surgery (MMS) occur in a small but clinically significant proportion of cases, with multiple management options available.

OBJECTIVEThis study aimed to compare recurrence-free survival (RFS) across different treatment modalities for positive margins after MMS to inform clinical decision making.

METHODSThis was a retrospective cohort study of 422 patients with positive margins after MMS from 2012 to 2022. Recurrence-free survival was analyzed using Kaplan-Meier methodology. Multivariable Cox regression adjusted for age, sex, immunosuppression, tumor characteristics, and anatomic location.

RESULTSAmong 388 patients in the primary analysis (306 curettage, 82 topical treatment), 3-year RFS was 92.6% (95% CI: 89.4%-95.9%) for curettage versus 82.7% (95% CI: 73.1%-93.6%) for topical treatment (p=.021). Topical treatment was independently associated with increased recurrence risk (adjusted hazard ratio 2.73, p=.021) after controlling for risk factors. Immunosuppression was the only other significant predictor of recurrence (adjusted hazard ratio 3.04, p = .036).

CONCLUSIONCurettage demonstrated superior 3-year RFS compared with topical treatment for positive margins after MMS, with an absolute difference of 9.9%. These findings support curettage as the preferred initial management approach for positive margins after MMS when clinically feasible.

Abstract from PubMed