The Prognostic Significance of Sentinel Lymph Node Status for Patients with Thick Melanoma

Background: Sentinel lymph node biopsy (SLNB) is recommended for patients with intermediate-thickness melanoma, but the use of SLNB for patients with thick melanoma is debated. This report presents a single-institution study investigating factors predictive of sentinel lymph node (SLN) metastasis and outcome for thick-melanoma patients. Methods: A retrospective review of a single-institution database from 1997 to 2012 identified 147 patients with thick primary cutaneous melanoma (≥4 mm) who had an SLNB. Clinicopathologic characteristics were correlated with nodal status and outcome. Results: The median age of the patients was 67 years, and 61.9 % of the patients were men. The median tumor thickness was 5.5 mm, and 54 patients (36.7 %) had a positive SLN. Multivariable analysis showed that only tumor thickness significantly predicted SLN metastasis (odds ratio 1.14; 95 % confidence interval (CI) 1.02–1.28; P = 0.02). The overall median follow-up period was 34.6 months. Overall survival (OS) and melanoma-specific survival (MSS) were significantly worse for the positive versus negative-SLN patients. Multivariable analysis showed that age [hazard ratio (HR) 1.04; 95 % CI 1.01–1.07; P = 0.02] and SLN status (HR 2.24; 95 % CI 1.03–4.88; P = 0.04) significantly predicted OS, whereas only SLN status (HR 3.85; 95 % CI 2.13–6.97; P < 0.01) significantly predicted MSS. Conclusions: Tumor thickness predicts SLN status in thick melanomas. Furthermore, SLN status is prognostic for OS and MSS in thick-melanoma patients, with positive-SLN patients having significantly worse OS and MSS. These findings show that SLNB should be recommended for thick-melanoma patients, particularly because detection of SLN metastasis can identify patients for potential systemic therapy and treatment of nodal disease at a microscopic stage.