Comparison of Survival Outcomes With/Without Adjuvant Radiation Therapy in Desmoplastic Melanoma

BACKGROUND: Desmoplastic melanoma (DM) is a rare variant of cutaneous melanoma with a high rate of local recurrence. Recent studies have indicated a potential benefit in local control with the addition of adjuvant radiotherapy (RT). OBJECTIVE: This study sought to evaluate the outcomes of adjuvant RT for patients with DM. MATERIALS AND METHODS: The National Cancer Database was queried (2004-2015) for patients with newly diagnosed, nonmetastatic DM. Patients were divided into 2 groups based on the adjuvant therapy they received: RT or observation. Statistics included multivariable logistic regression to determine factors predictive of receiving adjuvant RT, Kaplan-Meier analysis to evaluate overall survival (OS), and Cox proportional hazards modeling to determine variables associated with OS. RESULTS: There was no difference in median OS between patients treated with RT when compared with patients observed (111.4 months vs 133.9 months, p = .1312). On multivariable analysis, older age, T stage ≥2, N stage ≥1, and no receipt of immunotherapy were associated with worse OS. CONCLUSION: In this large study evaluating efficacy of adjuvant RT in DM, no overall survival benefit was observed among patients receiving adjuvant RT.