Prognostic factors in 161 patients with mucosal melanoma: a study of German Central Malignant Melanoma Registry

Abstract

Background: mucosal melanoma is a rare malignancy which represents approximately 1% of all melanomas. It is shown that mucosal melanomas have a different biology and less favourable prognosis than its cutaneous counterpart. Objectives: predictive and prognostic factors of survival for mucosal melanoma have not yet been elucidated. The aim of this study was to investigate risk factors affecting the course of mucosal melanoma patients followed in our clinic. Methods: one hundred and sixty-one patients with mucosal melanoma prospectively documented in the German Central Malignant Melanoma Registry (CMMR) were included in this study. Gender, age, localization, stage at first medical examination, tumour thickness and mutational status were documented. The American Joint Committee on Cancer (AJCC), 7th edition was used to define tumour stage. Kaplan-Meier survival curves were evaluated compared with the log-rank test. Multivariate Cox proportional hazard models were used to identify significant independent prognostic factors. Results: according to the localization, patients were categorized in 44.7% oral-nasal, 28.6% genital, 20.5% anorectal and 6.2% visceral. Genital mucosal melanomas had the most favourable 5-year OS rate (58.6%) followed by visceral (58.3%) and oral-nasal (39.3%). Anorectal melanomas had the worst OS time (median: 21 +/- 4.8 months) and 5-year survival rate (22.7%). Patients <60 years had a better survival than the older group (P = 0.013). Tumour stage at the time of the first medical examination was also a significant factor for survival (P = 0.001). Gender and mutational status were found to have no effect on survival. Age (HR = 2.1) and stage at first medical examination (Stage I vs. Stage IV; HR = 8.2) are shown to be significant independent prognostic factors on multivariate Cox regression analysis, but not localization. Conclusion: in this study, we observed that older age and advanced stage have significant negative effects on the survival of mucosal melanoma. Thus, the AJCC staging system is applicable for mucosal melanoma.