Chemotherapy in combination with anti-PD-1 agents as adjuvant therapy for high-risk oral mucosal melanoma

Background Adjuvant therapy plays a critical role in the treatment of oral mucosal melanoma (OMM). Anti-programmed cell death-1 (PD-1) agents are recommended as front-line therapy for metastatic melanoma, but their efficacy as adjuvant therapy for high-risk OMM remains unclear. Patients and methods A single-center, retrospective cohort study was conducted in 193 nodular-type oral mucosal melanoma (NOMM) patients who received chemotherapy alone or in combination with high-dose interferon-α2b (HDI) or anti-PD-1 agents as adjuvant therapy. Multivariate analysis was performed to identify significant prognostic factors for the 2-year overall survival (OS) and progression-free survival (PFS). Results Tumor thickness, ulceration and invasion level were found to be independent prognostic factors for both 2-year OS and PFS, while T-stage was only associated with OS. The 2-year OS and PFS were 43.5% and 10.9% in patients who received only chemotherapy. In comparison, the 2-year OS was improved, albeit not significantly (47.4%; p > 0.05), and PFS was significantly improved (43.6%; p = 0.0028) in patients who received chemotherapy plus HDI; and both 2-year OS (71.0%; p = 0.0118) and PFS (53.6%; p = 0.0001) were significantly improved in patients received chemotherapy plus anti-PD-1. The serious adverse event (SAE) ( p < 0.0001) and discontinued treatment due to SAE ( p < 0.0001) were significantly lower in patients who received anti-PD-1 than in patients who received HDI. Conclusions Invasion level and tumor thickness are independent prognostic factors for NOMM. Chemotherapy plus anti-PD-1 agents seem to be the adjuvant therapy of choice for NOMM, as it is safer and more tolerable than HDI and, more importantly, it can significantly improve the OS and PFS.