Attributes and risk factors of positive margins on 864 excisions of basal cell carcinomas: a single-center retrospective study.

Background: Residual tumors increase the likelihood of recurrence of basal cell carcinoma (BCC).Objective: We determined the attributes and risk factors for positive surgical margins (+SM) of excised BCC in a university hospital.Methods: In this cross-sectional retrospective study, we reviewed the histologic reports of BCC removed via conventional surgical excision (CSE) by specialists from different fields.Results: Among excised BCCs (n = 864), there was a predominance of nodular BCC (82.64%) in the facial H-area (72.81%; average diameter = 9.12 mm), which had the highest + SM rate (20.17%). Most cephalic (ce-BCC; 69.01%) and non-cephalic (91.11%) BCCs were excised by dermatologists, with low rates of + SM (4.53%; 1.46%, respectively); the overall + SM rate was 12.73%. Men had larger (p < .001) and more ulcerated (p = .04) BCC. An aggressive histologic pattern (Ag-P) (p < .04) and ulceration (p < .001) were correlated with tumor size on multivariate analysis. The risk for + SM increased in ulcerated ce-BCC (p = .02), BCC with Ag-P (p = .02), and in the H-area (p < .001), nasal (p = .007), and labial (p = .05) regions. ce-BCC excised by head-neck surgeons had a high chance of ulceration (p < .001) and Ag-P (p = .002).Conclusions: Ag-P and H-zone remain critical risk factors for + SM. Accordingly appropriate treatment protocols should be used to ensure low + SM rates via CSE.