Adjuvant therapy in mucosal melanoma: a single-center experience and review of the literature

Mucosal melanoma (MM) is an aggressive and rare subtype of melanoma, and it is associated with poor prognosis. Surgical resection remains the mainstay of the treatment for localized disease, and different from cutaneous melanoma, the impact of adjuvant therapy has not been clearly established. We retrospectively analyzed patients with surgically resected MM from the MD Anderson Cancer Center melanoma database from January 2000 to December 2019. The univariate log-rank test and multivariate Cox regression model were used to analyze the impact of adjuvant therapy on overall survival (OS) and relapse-free survival. A total of 246 patients with localized or locally advanced MM who underwent surgical resection were included. The median OS for all patients was 4.8 years [95% confidence interval (CI), 3.6-6], with median OS for the 125 patients who received adjuvant systemic therapy was 5.7 years (95% CI, 4.0-10.2) and 4.0 years (95% CI, 2.8-6.6) for the 121 patients who had only surgery or surgery plus radiation in the subanalysis, chemotherapy was associated with a longer OS (7.3 years; 95% CI, 4.4-NA) compared to immunotherapy (5.5 years; 95% CI, 2.8-NA). Cox regression analysis demonstrated lymph node involvement, Breslow thickness, and use of adjuvant systemic therapy were considered independent factors for OS. Adjuvant systemic therapy was associated with a significant survival benefit in patients with resected MM (HR 0.53; 95% CI, 0.34-0.82; P = 0.004). However, due to the retrospective nature of the study, prospective clinical trials are warranted to determine the optimal adjuvant treatment strategy for this patient population.