Clinical outcomes and patterns of failure of head and neck mucosal melanoma treated with multiple treatment modalities.

OBJECTIVES: The study aims to analyze the clinical characteristics of head and neck mucosal melanoma (MMHN) and the effects of multiple treatment modalities on distant metastasis, recurrence and survival rates to provide a reference for the individualized treatment of MMHN. METHODS: We retrospectively reviewed 262 patients with stage III-IVb MMHN treated from March 1986 to November 2018 at our cancer center. RESULTS: The median follow-up time was 34.0 months (range 1-262 months). The 5-year overall survival (OS), distant metastasis-free survival (DMFS) and disease-free survival (DFS) probabilities were 37.7%, 30.2%, and 20.3%, respectively. The 5-year OS rates for patients with stage III, stage IVA, and stage IVB MMHN were 67.0%, 24.1% and 8.3%, respectively (P < 0.001). A total of 246 (93.9%) patients received surgery, 149 (56.9%) patients received chemotherapy, and 69 (26.3%) patients received immunologic/targeted therapy. A total of 106 (40.5%) patients were treated with radiotherapy: 9 were treated with preoperative radiotherapy, 93 were treated with postoperative radiotherapy, and 4 were treated with radiotherapy alone. In the multivariate Cox regression analysis, primary tumor site, T stage, and immunologic/targeted therapy were independent factors for OS (all P < 0.05). Irradiation technique, T stage, and N stage were independent prognostic factors for DMFS (all P < 0.05). T stage, N stage, and surgery were independent prognostic factors for DFS (all P < 0.05). Distant metastasis was observed in 107 of 262 patients (40.8%), followed by local [74 (28.2%)] and regional [52 (19.8%)] recurrence. CONCLUSIONS: The main reason for treatment failure in MMHN is distant metastasis. Immunologic/targeted therapy and surgery are recommended to improve the survival of MMHN. The American Joint Committee on Cancer (AJCC) 8th edition staging system for MMHN does stage this disease effectively.