Optimizing local control in anorectal melanoma

Background: Wide local excision (WLE) of anorectal melanoma is associated with a high incidence of local recurrence. There is a paucity of literature on adjuvant radiation in this malignancy.
Aim: To identify the optimal method of local treatment in anorectal melanoma.
Settings and Design: Retrospective study in a tertiary cancer centre.
Materials and Methods: Records of 63 patients who presented between 1980 and 2004 were reviewed.
Results: Of the 63 patients, 18 were treated by either surgery with or without adjuvant radiation, or by radiation alone. The remaining had advanced disease and were offered only symptomatic treatment. The median overall survival in stage I patients was 12 months, while it was seven and four months in those with stage II and III disease respectively. The median survival in patients treated by WLE with adjuvant radiation (RT), WLE alone or Abdominoperineal resection (APR) was 34, 12 and 10 months respectively. Patients in whom the disease was confined to the mucosa had a better median overall survival than those in whom it had infiltrated beyond the mucosa (102 vs 11 months). The pattern of recurrence following WLE with adjuvant RT or APR was similar. None of the patients who received adjuvant RT after wide excision had a local or nodal recurrence.
Conclusion: Local treatment of anorectal melanoma should be individualized. WLE with adjuvant radiation seems to offer good locoregional control without reducing the survival and may be an option of treatment for patients with small, superficial anorectal melanoma. However, APR should be offered for patients with locally advanced disease or as a salvage following recurrence.

Keywords
Adjuvant radiation, anorectal melanoma, local control, mucosal melanoma