Basal-cell carcinoma (BCC) is the most common form of skin cancer and its incidence is still rising worldwide. Surgery is the most frequently used treatment for BCC, but large randomised controlled trials with 5-year follow-up to compare treatment modalities are rare. We did a prospective randomised controlled trial to compare the effectiveness of surgical excision with Mohs’ micrographic surgery (MMS) for the treatment of primary and recurrent facial BCC.

Between Oct 5, 1999, and Feb 27, 2002, 408 primary BCCs (pBCCs) and 204 recurrent BCCs (rBCCs) in patients from seven hospitals in the Netherlands were randomly assigned to surgical excision or MMS. Randomisation and allocation was done separately for both groups by a computer-generated allocation scheme. Tumours had a follow-up of 5 years. Analyses were done on an intention-to-treat basis. The primary outcome was recurrence of carcinoma, diagnosed clinically by visual inspection with histological confirmation. Secondary outcomes were determinants of failure and cost-effectiveness. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN65009900.

Of the 397 pBCCs that were treated, 127 pBCCs in 113 patients were lost to follow-up. Of the 11 recurrences that occurred in patients with pBCC, seven (4·1%) occurred in patients treated with surgical excision and four (2·5%) occurred in patients treated with MMS (log-rank test χ² 0·718, p=0·397). Of the 202 rBCCs that were treated, 56 BCCs in 52 patients were lost to follow-up. Two BCCs (2·4%) in two patients treated with MMS recurred, versus ten BCCs (12·1%) in ten patients treated with surgical excision (log-rank test χ² 5·958, p=0·015). The difference in the number of recurrences between treatments was not significant for pBCC, but significantly favoured MMS in rBCC. In pBCC, Cox-regression analysis showed no significant effects from risk factors measured in the study. In rBCC, aggressive histological subtype was a significant risk factor for recurrence in the Cox-regression analysis. For pBCC, total treatment costs were €1248 for MMS and €990 for surgical excision, whereas for rBCC, treatment costs were €1284 and €1043, respectively. Dividing the difference in costs between MMS and surgical excision by their difference in effectiveness leads to an incremental cost-effectiveness ratio of €23454 for pBCC and €3171 for rBCC.

MMS is preferred over surgical excision for the treatment of facial rBCC, on the basis of significantly fewer recurrences after MMS than after surgical excision. However, because there was no significant difference in recurrence of pBCC between treatment groups, treatment with surgical excision is probably sufficient in most cases of pBCC.

The Netherlands Organisation for Scientific Research ZonMW.