A Cochrane review «Surgical excision margins for primary cutaneous melanoma»1 «Sladden MJ, Balch C, Barzilai DA, Berg D, Freiman A, Handiside T, Hollis S, Lens MB, Thompson JF. Surgical excision margins for primary cutaneous melanoma. Cochrane Database Syst Rev 2009;(4):CD004835»1 included 5 studies with a total of 3 297 subjects with cutaneous invasive melanoma (not melanoma-in-situ where the melanoma cells are confined to the epidermis). Narrow margin definition ranged from 1 to 2 cm; wide margins ranged from 3 to 5 cm. Median follow-up ranged from 5 to 16 years. The summary estimate for overall survival favoured wide excision by a small degree (HR 1.04, 95% CI 0.95 to 1.15), but the result was not statistically significantly different. The summary estimate for recurrence free survival favoured wide excision (HR 1.13, 95% CI 0.99 to 1.28, p=0.06) but again the result did not reach statistical significance. There were insufficient data to perform a subgroup analysis of overall survival stratified by Breslow thickness.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and inadequate intention-to-treat adherence), and by inconsistency (heterogeneity in results in different populations).