Primary Tumor Size Predicts Distant Metastasis of Mucosal Malignant Melanoma in Head and Neck

To investigate the possible association between primary tumor size and overall survival and/or distant metastasis-free survival of patients with mucosal malignant melanoma of the head and neck. A total of 25 patients that have had primary tumor resection were enrolled in this study. Primary tumor size was assessed as the maximum size of the primary tumor in pathological and surgical reports. Patients with a primary tumor size of ≥43 mm showed a significant association with shorter overall survival (p=0.007) and distant metastasis-free survival (p=0.005) by the log-rank test. Multivariate survival analyses of two Cox's hazards proportional models showed that, in model1, pT4a-4b (p=0.01) and primary tumor size ≥43 mm (p=0.03) were significantly associated with shorter overall survival, and primary tumor size ≥43 mm (p=0.02) was significantly associated with shorter distant metastasis-free survival. In model2, pStage IVA-IVB (p=0.02) and primary tumor size ≥43 mm (p=0.03) were significantly associated with shorter overall survival, and primary tumor size ≥43 mm (p=0.02) was significantly associated with shorter distant metastasis-free survival. Large tumor size (≥43 mm) is a predictor of shorter overall survival and distant metastasis-free survival after primary tumor resection of mucosal malignant melanoma of the head and neck.