Outcome of basal cell carcinoma excision with 2 mm surgical margin in Japanese patients: A retrospective study of one-step surgery.

Background: Basal cell carcinoma is the most common skin malignancy. The standard treatment is surgical excision with predetermined margins. Some argue that the currently recommended surgical margins are excessive, and it is questionable whether such wide surgical margins should be applied to all lesions. We statistically investigated excisions with narrow margins and tried to identify the risk factors for recurrence after one-step surgery. Methods: Basal cell carcinomas were excised at a single institute in Japan over a six-year period and the recurrence rates were retrospectively analyzed using pathological reports and case notes. We reviewed the microscopic findings of the excised specimens and examined the excisional margin status, tumor subtype, and perineural invasion. Results: Forty-eight basal cell carcinomas (45 primary and 3 recurrent) that were identified in Japanese patients were included in this study. Among the primary lesions, well-pigmented and well-defined lesions did not show any involvement of the surgical margins, perineural invasion, or development of local recurrence. Recurrent lesions were significantly associated with positive surgical margins (side margin, P<0.01; deep margin, P<0.01) during the primary operation; however, no association was found with local recurrence after re-resection. Significant differences were observed in perineural invasion and the tumor subtype, especially in the aggressive subtype (P<0.05). Conclusions: A 2 mm margin allows for the safe excision of primary lesions with well-pigmented and well-defined basal cell carcinoma in Japan. Recurrent lesions can be treated with narrow margins by reconstruction after confirmation of a negative margin, instead of performing a common resection with wide margins.