A study suggested that a 1 cm excision margin is not large enough for excision of cutaneous melanoma with a Breslow thickness greater than 2 mm.1

A total of 900 patients with one primary localized cutaneous melanoma greater than 2 mm in Breslow thickness on their trunks or limbs were randomly assigned to surgery with either a 1 cm excision margin (453 patients) or a 3 cm excision margin (447 patients).

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Results showed 359 melanoma deaths out of a total of 494 deaths that occurred at a median follow-up of 8.8 years, (106 months [IQR 76 – 135]).

Out of the melanoma deaths, 194 occurred in the 1 cm group and 165 in the 3 cm group (unadjusted HR, 1.24; CI, 1.01 – 1.53; P = .041). Out of all patients, there was a larger number of deaths in the 1 cm group compared with the 3 cm group (253 vs 241, respectively).

However, the difference was not significant (unadjusted HR, 1.14 [95% CI, 0.96 – 1.36; P = .14). Surgical complications occurred more often in patients in the 3 cm group compared with patients in the 1 cm group (15% vs 8%, respectively).

The surgical excision guidelines for cutaneous melanoma with Breslow thickness greater than 2 mm is a 2 cm margin, with a 1 cm margin for those with less thickness.

The authors concluded that the adequacy of a 1 cm margin for thinner melanomas should be evaluated in future trials.


  1. Hayes AJ, Maynard L, Coombes G, et al. Wide versus narrow excision margins for high-risk, primary cutaneous melanomas: long-term follow-up of survival in a randomised trial [published online ahead of print January 11, 2016]. Lancet Oncol. doi: 10.1016/S1470-2045(15)00482-9