Anorectal Malignant Melanoma-Defining the Optimal Surgical Treatment and Prognostic Factors

Patients with anorectal malignant melanoma (ARMM) have a poor prognosis. Optimal surgical treatment is not defined. The aim of the study was to define the surgical treatment for ARMM, to compare the overall survival (OS) of abdomino-perineal resection (APR) and wide local excision (WLE) and to study various prognostic factors. Thirty patients of ARMM were managed, 20 with locoregional disease, 10 metastatic. Of the 20 patients with locoregional disease, 15 underwent APR and 5 WLE. The 1-, 2-, 3-, and 4-year overall survival rates (by Kaplan-Meier survival analysis) in the APR group were 67, 40, 40, and 32%, and in WLE group were 100, 100, 67, and 67% respectively. Median survival for APR and WLE groups were 13 and 36 months and were not significant (p 0.48). Node-negative patients had better survival than node positive in the APR group (56 vs. 13 months) (p 0.017). Patients with tumor size < 2cm, lymphovascular invasion and perineural invasion negative, and margin-negative and with superficial infiltration had a trend toward better survival than their counterparts. WLE gives an equivalent oncological outcome and can be offered for patients with smaller ARMM and APR for locally advanced, larger tumors or as a salvage following recurrence after WLE.