[Mohs micrographic surgery for repeat excision of basal cell carcinomas on the head with positive margins]

There is debate in the literature regarding the management of basal cell carcinoma following excision with positive surgical margins. While in some cases recurrence is not observed even after many years of follow-up, those in which recurrence does occur are at an increased risk of complications. Factors may exist that help to choose the best therapeutic approach for basal cell carcinomas on the head in which positive margins are observed following excision.

A total of 46 patients were selected who had been treated by Mohs micrographic surgery as a result of positive surgical margins being present following previous tumor excision. The factors associated with the absence of tumor nests and the occurrence of negative margins following a single Mohs stage were analyzed.

No associations were observed with sex, tumor size, affected margin (lateral, deep, or both), time since diagnosis, number of previous treatments, histological type, or tumor site. There was a certain trend towards more frequent identification of tumor nests when both surgical margins were affected and towards a requirement for a single Mohs stage in tumors less than 1.2 cm and in which less than 5 years had elapsed since diagnosis.

Conclusive data are unavailable with which to define cases in which repeat excision is necessary or those in which conventional excision could be sufficient. The best option for the treatment of these tumors is Mohs micrographic surgery, although conventional excision could be reasonable in small tumors located at low-risk sites and in which long periods have not elapsed since diagnosis.