Adjuvant GM-CSF Improves Survival in High-risk Stage IIIC Melanoma

Abstract

Stage III melanoma is associated with an increased risk of recurrence and death. Complete surgical resection remains the best chance for cure. Unfortunately, no adjuvant therapy has demonstrated a consistent improvement in melanoma-specific survival (MSS). We hypothesize that adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF) may improve clinical outcomes. Retrospective cohort study of 317 surgically resected stage III melanoma patients managed with observation or adjuvant GM-CSF at a single institution from 2001 to 2010. Of the 317 stage III patients, 165 (52%) were observed and 152 (48%) were treated with GM-CSF, with a median follow-up of 34 months. Patients treated with GM-CSF tended to be younger (P < 0.0001), had more advanced stage disease (P = 0.002), and were more likely to have had a recurrence before initiation of adjuvant therapy than the observation group (P < 0.0001). Adjuvant GM-CSF seemed to be associated with improved MSS, but this did not reach statistical significance (P = 0.08). Patients with stage IIIC melanoma derived a substantial benefit from adjuvant GM-CSF, with a 52% risk reduction in melanoma-specific death (hazard ratio 0.48; 95% confidence interval, 0.27-0.87; P = 0.02). Despite selecting patients with more advanced stage and a higher incidence of regional relapse, adjuvant GM-CSF was associated with an improved MSS but not disease-free survival in patients with stage IIIC disease. In patients not otherwise eligible for clinical trials, adjuvant GM-CSF treatment is a reasonable option for individuals with resected high-risk melanoma.