Multifactorial Analysis of Prognostic Factors and Survival Rates Among 706 Mucosal Melanoma Patients

Background: The hypothesis that mucosal melanomas from different anatomic sites would have different prognostic features and survival outcome was tested in a multifactorial analysis. Methods: Complete clinical and pathological information from 706 mucosal melanoma patients from different anatomical sites was compared for overall survival (OS) and prognostic factors. Results: Mucosal melanomas arising from different anatomical sites did not have any significant differences in OS in a multivariate analysis (p = 0.721). Among all 706 stage I–IV mucosal melanoma patients, depth of tumor invasion (p < 0.001), number of lymph node metastases (p < 0.001), and sites of distant metastases (p < 0.001) were independent prognostic factors for OS; among 543 stage I–III patients, depth of tumor invasion (p < 0.001) and number of lymph node metastases (p < 0.001) were independent prognostic factors for OS; and among 547 stage IV patients, depth of tumor invasion (p = 0.009), number of lymph node metastases (p < 0.001), and combined distant metastases and elevation of serum lactate dehydrogenase (LDH; p < 0.001) were independent prognostic factors for OS. The presence of c-KIT or BRAF mutations was not predictive of survival. Conclusions: This is the first large-scale study comparing outcomes of mucosal melanomas from different anatomic sites in a multifactorial analysis. There were no significant survival differences among mucosal melanomas arising at different sites when matched for staging and prognostic and molecular factors, thus rejecting our hypothesis. We concluded that prognostic characteristics of mucosal melanomas can be staged as a single histological group, regardless of the anatomic site of the primary tumor.