Staging and prognosis of mucosal melanomas of the head and neck

Background It remains unclear whether the current 8 th edition of the American Joint Committee on Cancer staging system (AJCC8) reliably predicts outcomes for patients with mucosal melanoma of the head and neck (MMHN). Although AJCC staging for MMHN has been modified from that recommended for cutaneous melanoma, it is uncertain how survival outcomes for MMHN compare with those for cutaneous melanoma of the head and neck (CMHN) when comparing AJCC stages. This study i) assessed the prognostic value of AJCC8 staging for MMHN, and ii) compared survival outcomes for MMHN and CMHN of the same disease stage. Methods A retrospective study of patients with MMHN, staged according to AJCC8, was conducted. Survival outcomes of interest were recurrence-free survival (RFS), distant metastasis-free survival (DMFS), melanoma-specific survival (MSS) and overall survival (OS). Kaplan-Meier and Cox regression models were used to compare survival between MMHN and CMHN of the same disease stage. Results The cohort consisted of 94 MMHN and 613 CMHN patients (Stage III and IV only). Overall, AJCC8 provided statistically-significant stratification of prognostic values for RFS, DMFS, MSS, and OS (all p <0.0001) in MMHN, except for segregation between T3 and T4a disease in MSS and OS. Survival outcomes were similar between MMHN and CMHN cohorts for RFS ( p= 0.56), DMFS, ( p= 0.24), MSS ( p= 0.76) and OS ( p= 0.71). Conclusions AJCC8 provides useful prediction of survival for MMHN, but better delineation between T3 and T4a tumors is required. Comparison of AJCC stages for patients with MMHN and CMHN demonstrated similar survival outcomes.