Otsuka M, Sugihara S, Mori S, et al. - As various cancers treated with the immune checkpoint inhibitor nivolumab exhibit better outcomes in correlation with immune-related adverse events (irAE), researchers sought to determine if the development of irAE is correlated with clinical efficacy via conducting a single-center retrospective study including patients with advanced mucosal melanoma (MM), receiving nivolumab monotherapy between August 2014 and September 2018. In the study cohort, 27 patients were included; these comprised 20 (74%), six (22%) and one (4%) patient with primary MM in the head and neck, genitourinary and anorectal regions, respectively. No significant correlation of the irAE onset with the objective response rate was observed in patients while it was identified to be significantly associated with the disease control rate. The median progression-free survival of 301 and 63 days was reported for patients with and without irAE, respectively. Results suggest a possible correlation of the development of irAE with improved survival in patients with MM treated with nivolumab monotherapy.