Mohs surgery against ordinary excision for facial basal cell carcinoma (Nijmegen trial)

Seven hospitals in the Netherlands randomised 408 primary and 204 recurrent high-risk facial basal cell carcinomas to Mohs micrographic surgery or to ordinary excision between October 1999 and February 2002. High risk meant a diameter of at least 1 cm, a location in the H-zone of the face, or an aggressive histological subtype. The two groups were randomised separately and are reported separately, which is the point of the trial: the question was not whether Mohs surgery works but in which tumours it is worth its cost.

At five years the difference in primary tumours was small and not significant: seven recurrences (4.1 per cent) after ordinary excision against four (2.5 per cent) after Mohs surgery, log-rank p=0.397. In recurrent tumours it was significant: ten recurrences (12.1 per cent) after ordinary excision against two (2.4 per cent) after Mohs surgery, p=0.015. Treatment cost 1,248 euros for Mohs surgery against 990 euros for excision in primary tumours and 1,284 against 1,043 euros in recurrent tumours, giving an incremental cost-effectiveness ratio of 23,454 euros for primary and 3,171 euros for recurrent disease. The trial's own conclusion at that point was that ordinary excision is probably enough for most primary tumours.

The ten-year report changed the shape of the answer without changing its statistics. Cumulative ten-year recurrence was 4.4 per cent after Mohs surgery against 12.2 per cent after excision for primary tumours (log-rank p=0.100) and 3.9 against 13.5 per cent for recurrent tumours (p=0.023). The number that matters most for the reader is this: 56 per cent of the recurrences in primary tumours happened more than five years after treatment, and 14 per cent of those in recurrent tumours. Any five-year trial in this disease, including this one, is reading half the story.