Utilization and survival benefit of adjuvant immunotherapy in resected high-risk stage II melanoma

Introduction: The risk of locoregional and distant recurrence of stage IIB/IIC cutaneous melanoma is high, and limited evidence exists on the clinical benefit of adjuvant immunotherapy (aIMT). This is the first retrospective study to evaluate the utilization and survival benefit of adjuvant immunotherapy (aIMT) for high-risk stage II cutaneous melanoma. Methods: The National Cancer Database (NCDB) was queried for stage IIB/IIC melanoma patients who underwent resection and sentinel lymph node biopsy. Chi-square tests and multivariable logistic regression examined associations between utilization of aIMT and socioeconomic and clinical characteristics. Propensity score weighted Cox proportional hazards model assessed impact of aIMT on overall survival. Results: Of the 8,549 patients with pathologic stage IIB/IIC melanoma, 344 (4.02%) patients received aIMT. Patients with pT4b disease or positive surgical margins were more likely to receive aIMT than patients with pT3b disease or negative margins (OR=3.10, OR=2.71, respectively, all P<0.001). Females or patients less than age 65 were more likely to receive aIMT (OR=1.36, OR=2.77, respectively, P<0.05). The Cox proportional hazard model demonstrated that receiving aIMT was associated with longer survival (HR=0.66, P<0.01). Conclusions: This study observed a survival advantage with utilization of immunotherapy for patients with resectable stage IIB/IIC melanoma. Sociodemographic differences on the receipt of aIMT warrant further attention.