Three-Year Analysis of Adjuvant Therapy in Postoperative Melanoma including Acral and Mucosal Subtypes

Background: Adjuvant therapy has improved the clinical prognosis for postoperative melanoma patients. but the long-term efficacy of acral and mucosal types has not been fully evaluated in previous trials. This study aimed to assess the 3-year recurrence-free survival (RFS) and overall survival (OS) of melanoma treated with anti-PD-1antibody (Ab) or the combination of dabrafenib and trametinib. Methods We retrospectively analyzed both the 3-year recurrence-free survival (RFS) and overall survival (OS). Results The median RFS was 18.4 months, with a range of 0.69 to 36 months. The 3-year RFS of the acral and mucosal types was 28.1% and 38.5%, respectively. Baseline tumor thickness (TT) and acral type were associated with the RFS in subgroup analysis. Moreover, we classified 104 acral and non-acral cutaneous patients into the anti-PD-1 Abs or dabrafenib plus trametinib combined therapies cohort in multiple analyses. The acral subtype and TT were detected as important prognostic factors. In the 3-year OS, only tumor ulceration was associated with the OS in both univariate and multiple analyses. Conclusion This study suggests that both acral and mucosal types in the adjuvant setting are less effective than non-acral cutaneous melanoma at the 3-year RFS.