Mucosal melanoma in 1481 patients in the Netherlands. An overview of metastatic patterns, main driver mutations and the efficacy of therapeutic strategies.

BACKGROUND: Mucosal melanomas are a rare melanoma subtype with poor prognosis. This project aimed to identify the main driver mutations of the different mucosal melanomas and to evaluate the efficacy of targeted/immunotherapies in patients with metastatic disease in current practice. In addition, the baseline clinicopathological characteristics, metastatic patterns, and primary treatment strategies and survival of mucosal melanoma subtypes were studied. METHODS: The Dutch nationwide pathology databank (Palga) and the Netherlands Comprehensive Cancer Organisation (IKNL) were queried for all patients with a diagnosis of mucosal melanoma (1989-2021). RESULTS: The dataset included a total of 1481 patients. Mutation status was assessed in 397 patients and in 170 patients (43%) a driver mutation was discovered. Patients with metastatic disease who received targeted/immunotherapy did show a better survival. The liver and lung were the predominant locations of the first metastasis. CONCLUSIONS: The data in the present study implies that patients with metastatic disease mucosal melanoma might benefit from targeted/immunotherapies. Molecular analysis should be considered in these patients.