Study Supports Smaller Margins in Excising Thicker Melanomas

Patients with a primary cutaneous melanoma thicker than 2 mm can be safely treated with a 2-cm resection margin, according to the results of a study conducted at 9 European centers.

In fact, patients who were assigned to a 2-cm resection margin had a similar overall survival and recurrence-free survival at 5 years as patients who had a 4-cm resection margin.

Peter Gillgren, MD, with the Karolinska Institutet in Stockholm, Sweden, and colleagues elsewhere randomized 936 patients with cutaneous melanoma thicker than 2 mm, at clinical stage IIA-C, to either a 2-cm or 4-cm resection margin.

The optimal excision margin for patients with localized cutaneous melanoma thicker than 2 mm is still contested, the researchers point out.

A narrow excision may increase the risk of relapse, which may, in turn, decrease disease-free and overall survival. On the other hand, a wide excision may be associated with surgical difficulties, poor cosmetic results, lymphedema, prolonged hospitalization, split skin grafting, or complicated skin flap reconstructions.

Most international guidelines favor an excision margin of 2 cm to 3 cm for thick tumors; however, there are limited data to support this recommendation.

Study participants were aged ≤75 years with clinically localized disease on the trunk, or upper or lower extremities, and had not undergone surgical staging before randomization.

After a median follow-up of 6.7 years, 181 (39%) of 465 patients in the 2-cm group and 177 (38%) of 471 patients in the 4-cm group had died (hazard ratio 1.05; 95% CI, 0.85-1.29; P = .64).

Five-year overall survival was 65% in both groups (2-cm group 95% CI, 60-69; 4-cm group 95% CI, 60- 70; P = .69). Recurrence-free survival was 56% in both groups at 5 years (95% CI, 51-61; P = .82).

Split skin grafts were used in 58 (12%) patients in the 2-cm group and 223 (47%) in the 4-cm group, and a surgical flap in 19 (4%) and 27 (6%) patients, respectively.

Gillgren and colleagues point out that their study was intended to be an equivalence trial with a target recruitment of 2000 patients, but fewer than 1000 patients enrolled, and the study was thus stopped early. They were quick to emphasize, however, that their study is the largest randomized controlled trial of surgical excision margins for thick melanomas and offers “the best evidence yet about the size of surgical excision margins.”

The incidence of cutaneous melanoma is increasing in Scandinavia and other countries with primarily Caucasian populations, the authors noted in their article. Disease-related mortality has also increased in most light-skinned populations worldwide in recent years.

Gillgren P, Drzewiecki KT, Niin M, et al. 2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: a randomised, multicentre trial [published online ahead of print October 24, 2011]. Lancet. 2011;378(9803):1635-1642. http://dx.doi.org/1548.