Presenter(s)
A. C. Gober1, J. Beiriger1, M. Berry1, J. Alt1, H. Mccrary2, and Y. J. Hitchcock3; 1University of Utah, Salt Lake City, UT, 2University of Utah, Salt Lake City, UT, United States, 3Department of Radiation Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
Purpose/Objective(s): Due to its rarity and poor prognosis, the roles of perioperative therapies in the treatment of head and neck mucosal melanoma (HNMM) are not well defined. This study aims to assess the impact of adjuvant radiation therapy (RT) and immunotherapy (IO) on survival in patients treated with surgical resection for HNMM.
Materials/Methods: Retrospective chart review was conducted to identify patients with HNMM treated at a single academic institution from 2005-2025. Patients with primary mucosal melanoma outside of the head and neck, and those who were treated with palliative intent were excluded. Data points specific to treatment modality (surgery, RT, and IO) were collected. Overall survival (OS) was analyzed using Kaplan-Meier curves with log-rank tests for group comparisons. Cox proportional hazards models were used to analyze the impact of each treatment modality on OS.
Results:
Thirty-one patients with HNMM were identified in the predefined treatment window. The median age at diagnosis was 66 years. Nasal cavity was the most common primary site, representing 58% of all cases, followed by oral cavity (29%) and paranasal sinuses (13%). Twenty-five patients underwent surgical resection and were included in the treatment analysis. Eighteen patients received adjuvant RT, and IO was administered to 44% of patients, despite BRAF, RAS, and KIT mutational burden being low (n=4) in this cohort. Median OS for patients receiving definitive therapy was 32.8 months. Patients who received combination RT and IO adjuvantly had the highest survival rates, with a 5-year OS of 51.4%. Patients treated with adjuvant RT alone had a median survival of 63.7 months. On multivariate Cox regression model accounting for multi-modality therapy and initial stage of disease, RT was independently associated with improved OS (HR = 0.14, p=0.006). Systemic therapy trended toward improved OS but did not reach statistical significance in this small cohort (HR 0.25, p=0.3). Median progression-free survival for the entire cohort was 4.63 months. Distant metastatic disease remained an important predictor of mortality, with a 1-year distant metastasis-free survival of 60%.Conclusion: In this single-institution retrospective study, we demonstrate improved survival for patients with HNMM compared to historical data. While the sequencing of perioperative therapies is evolving, patients in our study benefited from combined modality therapy (RT + IO) after resection. Despite high distant failure rates, adjuvant RT improved outcomes irrespective of systemic therapy use.