Excision Margin and Survival in Patients with High-Risk, Primary Cutaneous Melanoma: A Retrospective Study Based on Surveillance Epidemiology and End Result (SEER) Database.

Objectives: The optimal excision margin of primary cutaneous melanoma greater than 2 mm in thickness is still a controversial topic. The aim of the present study was to compare the long-term survival between narrow and wide excision margins in the surgical excision of patients with high-risk primary melanoma.

Methods: We chose the patients with primary melanoma of the skin thicker than 2 mm in The Surveillance, Epidemiology, and End Results database. Patients were divided into a narrow margin group (1-2 cm) and a wide margin group (>2 cm) according to the resection margin information. The primary outcome was overall survival and disease-specific survival.

Results: From 2004 to 2015, a total of 2,772 patients diagnosed as having melanoma of the skin were recruited into this study and were assigned to the narrow margin group (n = 1996) and the wide margin group (n = 776). A total of 1,098 patients died during the follow-up, and 681 of these were due to melanoma. There were 779 deaths in the narrow margin group and 319 deaths in the wide margin group (HR: 0.96, 95% CI: 0.84-1.10, p = 0.26). A total of 490 melanoma-specific deaths were reported in the narrow margin group and 191 were reported in the wide margin group (HR: 1.01, 95% CI: 0.85-1.19, p = 0.91).

Conclusions: Wider excision margin greater than 2 cm did not provide any additional therapeutic benefits compared to narrow excision margin between 1 and 2 cm. A 2-cm margin is adequate and safe for high-risk primary melanoma of the skin thicker than 2 mm.