Records of 30 patients treated for malignant melanoma of the anal canal during the years 1948-96 were reviewed retrospectively. Most of them at the time of diagnosis were locally advanced - the median tumor diameter was 6.5 cm and the penetration of all tumors was deeper than 5 mm according to the Breslow classification. Surgery with intention of complete removal was performed on 25 of these patients and in 19 cases was considered to be microscopically complete: 7 abdominoperineal resections (APR) and 12 local excisions (LEX). Nine out of these 12 LEX were primarily done outside of our institution and can be considered only as excision biopsies. The median disease free survival time after APR was 4.25 month and after LEX was 9 month. Local recurrence was found in 4 out of 6 patients surviving after APR, and in 10 out of 12 after LEX. The median survival time after APR was 13 months, comparing with 21 months after LEX. Only one patient, a female, survived more than 5 years. She was treated by primary wide local excision, and the same procedure was done for her local recurrence. Two patients are still living 13 month after LEX + inguinal-iliac lymphadenectomy + radiation therapy without local recurrence or distant metastases. The authors support the hypothesis that survival of patients with malignant melanoma originating in the anal canal is not closely related to the aggressiveness of the primary surgery. The biology of the tumor and the clinical-pathological stage at presentation seem to be the most important prognostic factors. The authors believe that wide local excision should be recommended for all cases of 3 cm or less in diameter, and less than 3 mm of penetration according to the Breslow staging system. APR may be the procedure of choice for bigger and more penetrating lesions. Radiation therapy should be more widely employed, particularly in cases after LEX and in cases when primary surgery is contraindicated.

Keywords: anorectal melanoma, abdomino-perineal resection, local excision