To compare Mohs’ micrographic surgery (MMS) to conventional surgical excision in the treatment of facial basal cell carcinoma (BCC).

Prospective, randomised, unblinded trial (www.controlled-trials.com; ISRCTN65009900).

408 cases of primary facial BCC and 204 cases of first and second recurrent facial BCC from 7 hospitals in the Netherlands were randomly assigned to either excision or MMS. The primary outcome was clinically diagnosed local recurrence of carcinoma, with histological confirmation. Secondary outcomes were cost-effectiveness and risk factors for treatment failure. Statistical analysis was performed according to the intention-to-treat principle.

After 5 years follow-up, 7 primary BCCs (4.1%) recurred after excision, compared to 4 (2.5%) after MMS treatment (logrank test, chi-squared: 0.718, p = 0.397). The difference in number of recurrences was not statistically significant. Cox regression analysis revealed no significant effects from risk factors measured in the study. The total treatment costs were € 1248 for MMS and € 990 for excision. In the group of recurrent BCCs, after 5 years follow-up recurrence occurred in 2 cases (2.4%) after MMS treatment, versus 10 cases (12.1%) after excision (logrank test, chi-squared: 5.90, p = 0.015). The effectiveness of MMS was significantly higher. Cox regression analysis showed that an aggressive histological subtype was a significant risk factor for recurrence. The total treatment costs were € 1284 for MMS and € 1043 for excision.

In primary facial BCC there is no statistically significant difference in number of recurrences between MMS and excision. In recurrent facial BCC, MMS is preferred to excision, based on a lower number of second and third recurrences.