Final Results of the Sunbelt Melanoma trial: A multi-institutional prospective randomized phase III study evaluating the role of adjuvant high-dose interferon alfa-2b and completion lymph node dissection for patients staged by sentinel lymph node biopsy

Purpose: The Sunbelt Melanoma Trial is a prospective randomized trial evaluating the role of high-dose interferon alfa-2b therapy (HDI) or completion lymph node dissection (CLND) for patients with melanoma staged by sentinel lymph node (SLN) biopsy. Patients and Methods: Patients were eligible if they were age 18 to 70 years with primary cutaneous melanoma ≥ 1.0 mm Breslow thickness and underwent SLN biopsy. In Protocol A, patients with a single tumor-positive lymph node after SLN biopsy underwent CLND and were randomly assigned to observation versus HDI. In Protocol B, patients with tumor-negative SLN by standard histopathology and immunohistochemistry underwent molecular staging by reverse transcriptase polymerase chain reaction (RT-PCR). Patients positive by RT-PCR were randomly assigned to observation versus CLND versus CLND+HDI. Primary end points were disease-free survival (DFS) and overall survival (OS). Results: In the Protocol A intention-to-treat analysis, there were no significant differences in DFS (hazard ratio, 0.82; P =.45) or OS (hazard ratio, 1.10; P =.68) for patients randomly assigned to HDI versus observation. In the Protocol B intention-to-treat analysis, there were no significant differences in overall DFS (P =.069) or OS (P =.77) across the three randomized treatment arms. Similarly, efficacy analysis (excluding patients who did not receive the assigned treatment) did not demonstrate significant differences in DFS or OS in Protocol A or Protocol B. Median follow-up time was 71 months. Conclusion: No survival benefit for adjuvant HDI in patients with a single positive SLN was found. Among patients with tumor-negative SLN by conventional pathology but with melanoma detected in the SLN by RT-PCR, there was no OS benefit for CLND or CLND+HDI.