Surgical treatment for anorectal malignant melanoma: report of five cases and review of 79 Japanese cases

Anorectal malignant melanoma (AMM) is a relatively rare disease. Because of its poor prognosis, the optimal surgical treatment for AMM is still controversial and difficult to determine. In this paper, we report five cases of AMM that have been treated by surgery and/or other methods at Shinshu University Hospital within the last decade. We also review the present five cases along with 74 other Japanese cases reported between 1997 and 2006 and discuss the role of surgery in the treatment of AMM. Among our AMM patients, two who underwent radical abdominoperineal resection had long survival, while the other three patients who underwent palliative surgery had a poor outcome. On the total of 79 AMM patients, those who underwent curative surgery had a better outcome than those who underwent palliative surgery (p < 0.0001). Furthermore, the outcome of AMM patients at stages 0 and I was better than that of AMM patients at stages II, III, and IV (p < 0.0001). There was no significant difference in survival between AMM patients with and without adjuvant chemotherapy. In conclusion, AMM patients treated by curative surgery can expect long-term survival, although the usefulness of adjuvant chemotherapy for AMM patients is controversial.