ANORECTAL MELANOMA - AN INCURABLE DISEASE

PURPOSE: This study was designed to describe recurrence and survival r ates after operative treatment for anorectal melanoma and to identify predictive factors for recurrence. METHODS: Records of 50 patients wit h anorectal melanoma from 1939 to 1993 were reviewed. RESULTS: Overall five-year survival and disease-free survival were 22 and 16 percent, respectively. At the time of diagnosis, 26 percent of patients had met astatic disease, and all died within 12 (mean, 6.3) months. Five-year survival and recurrence rates were identical after either abdominoperi neal resection (APR) or wide local excision, both with curative intent . Gender, size of tumor, presence of melanin, positive perirectal lymp h nodes, or treatment were not predictive of recurrence. Anorectal mel anoma was found incidentally after hemorrhoidectomy or polypectomy in five patients. Three other patients underwent an excisional biopsy of a lesion measuring less than 2 cm. Of these eight patients, five under went APR and three underwent wide local excision with no microscopic r esidual tumor at pathology. All developed regional or systemic recurre nce at a mean of 21 (range, 4-88) months, and all died of their diseas e at a mean of 29 (range, 5-98) months. CONCLUSION: Prognosis for anor ectal melanoma is poor, irrespective of surgical treatment performed. No predictive factors for recurrence were identified in this series. W ide local excision with a negative margin of a least 1 cm is suggested as the treatment of choice. APR should be reserved for tumor not amen able to local excision or for palliative treatment of large obstructiv e lesion until effective adjuvant therapies are available.