Prognostic values of treatment modalities on head and neck mucosal melanomas in elderly patients: a population-based analysis

BACKGROUND: Head and neck mucosal melanoma (HNMM) is defined as a rare malignant tumor derived from melanocytes. There is no consensus regarding the treatment protocol for HNMM in elderly patients. METHODS: The National Cancer Institute’s Surveillance, Epidemiology, and End Results database was used to identify elderly patients diagnosed with HNMM from 1975 to 2016. The chi-squared test was used to compare patient characteristics. The reverse Kaplan-Meier method was used to estimate the median follow-up time. The Kaplan-Meier method and log-rank test were used to estimate and compare the overall survival (OS) and disease-specific survival (DSS) of the groups. Cox regression analysis was used to evaluate the risk factors for OS and DSS of HNMM. RESULTS: Our retrospective study included 828 elderly patients with HNMM, and the 5-year OS and DSS rates were 22.4% and 27.4%, respectively. After adjusting for other variables in multivariate analysis, patients undergoing radiotherapy alone had worse OS [hazard ratio (HR) =1.449, 95% confidence interval (CI): 1.010–1.742, P=0.006] and DSS (HR =1.656, 95% CI: 1.257–2.181, P<0.001) than those undergoing surgery alone. No significant difference in OS (HR =0.892, 95% CI: 0.753–1.056, P=0.183) or DSS (HR =0.917, 95% CI: 0.764–1.101, P=0.354) was observed for patients undergoing surgery with or without radiotherapy. Our analysis of the subgroup of patients with complete clinical staging information demonstrated that the effects of surgery alone on OS (HR =0.734, 95% CI: 0.562–0.958, P=0.023) were inferior to those of surgery with radiotherapy, but no significant difference was noted compared with radiotherapy alone. CONCLUSIONS: The survival of elderly patients with HNMM is increased with the combination of surgery and radiotherapy compared with surgery alone and radiotherapy alone. In addition, the population-based analysis demonstrated that combination therapy exhibited an obviously increased usage rate from 1975 to 2016, representing a mainstream treatment modality.