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.