Background: Rates of recurrence of facial basal-cell carcinoma are consistently lower after Mohs' micrographic surgery (MMS) than after other treatments, such as surgical excision (SE). However, MMS is more time-consuming and therefore more expensive than SE. We investigated the types of facial basal-cell carcinomas in which MMS was more effective than SE.
Methods: 408 primary and 204 recurrent facial carcinomas (374 and 191 patients, respectively) were analysed separately in this prospective randomised study. Patients were assigned SE or MMS (each 204 primary, 102 recurrent), and received treatment at two hospitals in the Netherlands. The primary outcome was recurrence of carcinoma. Analysis was by intention to treat.
Findings: Of the basal-cell carcinomas included in the trial, 397 primary (198 MMS, 199 SE) and 201 recurrent (99, 102) tumours were actually treated. Of patients with primary carcinomas, 21 had both MMS and SE on different tumours. Nine with recurrent carcinomas had both treatments on different skin tumours. 66 primary and 13 recurrent carcinomas were lost to follow-up. Of the primary carcinomas, five (3%) recurred after SE compared with three (2%) after MMS during 30 months of follow-up. Of the recurrent carcinomas, three (3%) recurred after SE and none after MMS during 18 months of follow-up. Four recurrent carcinomas randomly assigned to the SE group were treated with MMS. Although both differences favoured MMS, they were not significant (primary, difference 1% [95% CI -2.5% to 3.7%], p=0.724; recurrent, 3.2% [-2.0% to 5.0%], p=0.119). Total operative costs of MMS were higher than those of SE (primary 405.79 Euros vs 216.86 Euros, recurrent 489.06 Euros vs 323.49 Euros; both p<0.001).
Interpretation: No definitive conclusion on recurrence rates of primary or recurrent basal-cell carcinomas is yet possible. Although recurrence rates were lower after MMS than after SE, the differences were not significant.