SURGICAL MARGINS AND PROGNOSTIC FACTORS IN PATIENTS WITH THICK (GREATER-THAN-4 MM) PRIMARY MELANOMA

Background: Randomized trials have demonstrated the efficacy of 1- and 2-cm excision margins for thin and intermediate-thickness melanomas, respectively. The optimal margin of excision for thick melanomas is st ill unknown, however. We evaluated whether the margins used for interm ediate-thickness melanomas can be applied safely to thicker lesions. M ethods: The charts of 278 patients with thick primary melanomas treate d between 1985 and 1996 were retrospectively reviewed. Patients with d istant metastases at presentation or with followup less than 6 months were excluded. Median follow-up was 27 months. Known melanoma prognost ic factors and excision margins were evaluated for their impact on loc al recurrence (LR), disease-free survival (DFS), and overall survival (OS). Results: Median tumor thickness was 6.0 mm, and 57% were ulcerat ed. At presentation, 201 patients (72%) were node negative and 77 (28% ) were node positive (palpable or occult). The 5-year OS and DFS rates were 55% and 30%, respectively. The LR rate for all patients was 12%. Although nodal status, thickness, and ulceration were significantly a ssociated with OS by multivariate analysis, neither LR nor excisional margin (<2 cm vs. >2 cm) significantly affected DFS or OS in these pat ients. Conclusions: Because margins of excision greater than 2 cm do n ot improve LR, DFS, or OS compared to a margin of 2 cm or less, a 2-cm margin of excision is adequate for patients with thick melanoma. Beca use nodal status is a significant prognostic factor in these patients, staging by sentinel node biopsy should be considered in patients with thick melanomas and clinically negative nodal basins to allow proper entry and stratification in adjuvant therapy trials.