Immunotherapy in sinonasal melanoma: treatment patterns and outcomes compared to cutaneous melanoma.

BACKGROUND: Although treatment with checkpoint blockade is now accepted as standard of care for cutaneous melanoma, few studies have investigated its role in sinonasal melanoma (SNM). We aimed to evaluate whether immunotherapy was associated with improved survival in SNM and to compare the effect of immunotherapy in metastatic sinonasal and cutaneous melanoma. METHODS: This was a cohort study of patients included in the United States National Cancer Database who had been diagnosed with sinonasal or cutaneous melanoma between 2012 and 2015 and had complete information regarding immunotherapy status. The primary outcome was overall survival. The influence of immunotherapy on overall survival was compared by Kaplan-Meier and Cox proportional hazards models. Propensity score matched analyses between SNM patients who received immunotherapy and those who did not were based on clinicopathological covariates associated with survival in univariate Cox models. RESULTS: The analytic cohort consisted of 704 patients with SNM, 94 of whom were treated with immunotherapy and 152,896 patients with cutaneous melanoma, 8055 of whom were treated with immunotherapy. Immunotherapy was not associated with survival in the propensity-score matched cohort (n = 195; hazard ratio [HR] = 1.0; 95% confidence interval [CI], 0.7 to 1.5; p = 0.88) or in adjusted Cox proportional hazards model (n = 549; HR = 1.0; 95% CI, 0.74 to 1.4; p = 0.88). Regimens including immunotherapy were associated with improved overall survival in metastatic cutaneous melanoma (HR = 0.57; 95% CI, 0.49 to 0.66; p < 0.0001), but not metastatic SNM (HR = 1.1; 95% CI, 0.67 to 1.7; p = 0.75). CONCLUSION: Compared to current standard of care therapy, inclusion of immunotherapy as first-line therapy was not associated with improved survival in SNM.