Prognostic information from sentinel lymph node biopsy in patients with thick melanoma

Hypothesis: Sentinel lymph node (SLN) biopsy provides valuable prognostic information for patients with thick (T4) melanoma. Design: Post hoc analysis of data from a prospective, randomized trial. Setting: Academic and private hospitals. Patients: Data of 240 patients with melanoma thicker than 4 mm were analyzed. Patients with tumor-positive SLNs underwent completion lymphadenectomy. Diseasefree and overall survival were evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were performed to evaluate factors predictive of tumorpositive SLNs and disease-free and overall survival. Results: Median thickness of melanoma was 5.6 mm, and patients were followed up for amedian 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. Conclusion: The SLN biopsy provides useful prognostic information for patients with T4 melanoma.