Immunotherapy as a treatment modality for mucosal melanoma of the head and neck: A systematic review

Introduction: Mucosal melanoma (MM) is a rare disease, accounting for approximately 1.4% of all melanomas and only 0.03% of all new cancer diagnoses. Traditionally, it has been associated with a poor prognosis, with an overall 5-year survival rate of <25%. Progress in treatment has been hindered by its rarity and lack of evidence. However, studies on the treatment of subcutaneous melanoma with immunotherapy have demonstrated significant improvement in survival rates and have become a core part of oncological strategies. This paper discusses the revision of the evidence for the use of immunotherapy in the head and neck. Methods: This systematic review was conducted on January 19, 2019. The Medline and Embase databases were searched. In total, 509 articles were collated and screened. Inclusion criteria for the study included treatment-naive cohorts, cohorts with recurrent disease, primary outcomes with overall survival and disease-free survival at 5 years and at the longest follow-up, and studies of adults with MM in whom immunotherapy was reported as a treatment strategy. The exclusion criteria included duplicate papers, anatomical sites other than the head and neck, case reports, and those not published in English. Results: Fifty-two papers out of the 509 collated papers met the inclusion criteria. The results are shown as a comparison of yearly survival rates following different treatment modalities (immunotherapy vs nonimmunotherapy) at 2, 3, and 5 years. It was found that, with immunotherapy, survival rates at all intervals were higher than those without immunotherapy. Discussion: Immunotherapy outcomes in small studies have shown good data for increasing survival rates at yearly intervals in MM of the head and neck. Larger clinical trials are needed to accurately distinguish the efficacy and survival outcomes of immunotherapy when compared with treatment modalities, excluding immunotherapy. However, the ability to perform larger trials is limited by the rarity of MM of the head and neck.