Recurrence patterns among patients with sinonasal mucosal melanoma: A multi-institutional study.

Objective: To evaluate recurrence patterns and survival after recurrence among patients with sinonasal mucosal melanoma (SNMM).

Methods: This was a multi-institutional retrospective review from seven U.S. institutions of patients with SNMM from 1991 to 2022. Recurrence was categorized as local, regional, distant, or multifocal. Kaplan-Meier tests were used to evaluate disease-free survival (DFS), overall survival (OS), and post-recurrence survival (PRS) reported with standard errors (SE) and log-rank testing used for comparison. Cox-regression was further used, with hazard ratios (HR) and 95% confidence intervals (CI) reported.

Results: Among 196 patients with SNMM, there were 146 patients with recurrence (74.5%). Among all patients, 60-month DFS (SE) was 15.5% (2.9%), 60-month OS (SE) was 44.7% (3.7%), mean age ± standard deviation at diagnosis was 69.7 ± 12.5 years, and 54.6% were female. In 26 patients who underwent primary treatment of the neck, 60-month DFS did not differ from no treatment (p > 0.05). Isolated distant recurrence was most common (42.8%), followed by local (28.3%), multifocal (20.7%), and regional recurrence (8.3%). Among patients with regional recurrence in the neck, there was no 60-month PRS benefit for patients undergoing salvage neck dissection or radiation (p > 0.05). Among patients with distant recurrence, only immunotherapy was associated with improved 12-month PRS (HR = 0.32, 95% CI = 0.11-0.92, p = 0.034), and no treatment group was associated with improved 24- or 60-month PRS (p > 0.05).

Conclusion: SNMM is associated with a high recurrence rate and poor survival. Primary treatment of the neck was not associated with reduced recurrence, and immunotherapy for treatment of distant recurrence was associated with increased 12-month PRS.