Predictors for margin of resection >4 mm in the management of periocular basal cell carcinoma

Purpose: To determine the margin of resection (MOR) for periocular basal cell carcinoma (BCC) and compare the outcomes of BCC treatment, namely Mohs micrographic surgery (MMS) and wide excision with later reconstruction (WELR). Methods: This is a retrospective, comparative, interventional study of patients who underwent surgical treatment of periocular BCC. One hundred forty-two patients were included. One hundred patients were treated with MMS and 42 with WELR. Inclusion criteria were primary periocular BCC with postoperative follow-up of ≥6 months, age more than 18-year-old. Exclusion criteria were, orbital extension, BCC origin outside the periocular area, or those associated with Gorling or nevoid BCC. The main outcome measure was variables associates with MOR >4 mm. Results: There was a positive correlation between the preoperative tumor horizontal and vertical diameter with the corresponding MOR, of 0.27 (p = 0.01) and 0.28 (p = 0.007), respectively. Receiver operating characteristics suggest that a tumor with a horizontal diameter ≥5 mm or a vertical diameter of ≥6 mm, might need MOR >4 mm. One patient in the MMS group had BCC recurrence compared to none in the WELR group, and one patient in the WELR had a positive surgical margin, which was cleared during the reconstruction. Conclusions: BCC tumor margins may extend far beyond clinical margins and the MOR required is often more than 3-4 mm. MMS ensures clear tumor margins but is not practical for all patients. A stratification system could help divide patients between the treatment strategies.