Prognostic Information From Sentinel Lymph Node Biopsy in Patients With Thick Melanoma

Abstract

Sentinel lymph node (SLN) biopsy provides valuable prognostic information for patients with thick (T4) melanoma. Post hoc analysis of data from a prospective, randomized trial. Academic and private hospitals. Data of 240 patients with melanoma thicker than 4 mm were analyzed. Patients with tumor-positive SLNs underwent completion lymphadenectomy. Disease-free and overall survival were evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were performed to evaluate factors predictive of tumor-positive SLNs and disease-free and overall survival. Median thickness of melanoma was 5.6 mm, and patients were followed up for a median of 50 months. The SLNs were tumor positive in 100 patients (41.7%); 18% of these had additional positive nodes on completion lymphadenectomy. Extremity tumor location (risk ratio, 1.66; 95% confidence interval, 1.24-2.24; P = .001), Clark level (1.95; 1.33-2.87; P = .02), and lymphovascular invasion (1.57; 1.13-2.17; P = .01) were associated with a greater risk of tumor-positive SLNs. The patients with tumor-negative SLNs had significantly better median disease-free survival (46.5 vs 31.0 months; P = .04) and overall survival (55.5 vs 43.0 months; P = .004) compared with patients with tumor-positive SLNs. On multivariate analysis, male sex (risk ratio, 1.59; 95% confidence interval, 1.05-2.50; P = .02), increasing Breslow thickness (1.58; 1.10- 2.30; P = .03), ulceration (1.73; 1.18-2.59; P = .02), and tumor-positive SLNs (1.68; 1.17-2.43; P = .009) were associated with worse overall survival. The SLN biopsy provides useful prognostic information for patients with T4 melanoma.