Long term follow up of survival in a randomised trial of wide or narrow excision margins in high risk primary melanoma.

Background: In the past there has been controversy concerning the necessary margin of excision for cutaneous melanomas greater than 2mm in thickness. Our previous report of a randomised trial of 1cm versus 3cm excision margins for this high risk group showed that narrow margins were associated with an increased rate of loco-regional relapse but there was no statistically significant difference in overall survival at a median follow-up of 5 years. We now report long term survival analysis of that trial. Methods: Patients from the UK and Poland with single primary localised cutaneous melanoma greater than 2mm in Breslow thickness were randomised 1:1 to a 1cm or 3cm excision margin. This analysis focusses on overall survival and melanoma-specific survival endpoints in the intention-to-treat population. Findings: Between 1993 and 2001, 453 patients were randomised to receive a 1cm excision and 447 were randomised to receive a 3cm excision. At a median follow-up of 106 months (IQR 76-135 months), a total of 494 patients have died with 359 of these deaths attributed to melanoma. There were 194 deaths attributed to melanoma in the 1cm group compared with 165 in the 3cm group (hazard ratio 1·24; 95% CI 1·00-1·52; P=0·047). While there was a higher number of deaths overall in the 1cm group compared to the 3cm group (253 versus 241) no statistically significant difference in overall survival was observed (hazard ratio 1·14: 95% CI 0·96-1·36, P=0·143). Interpretation: With longer follow-up, we observe a significant increase in melanoma-specific mortality in the narrow margins group, but no significant overall excess of deaths.