Management of anorectal melanomas: a 10-year review

Abstract

Background: Anorectal melanoma (AM) is a rare tumour with poor prognosis. The primary modality of treatment for AM is surgery. However, the choice of operation is controversial. Historically, radical operations like abdominoperineal excision of rectum (APER) with or without inguinal lymph node dissection were preferred. However, as no stage-specific survival advantage has been seen with APER later studies have recommended wide local excision (WLE) as the preferred treatment where negative margins can be achieved. The aim of our study was to review our results.

Methods: Inpatient and outpatient charts of all patients treated for AM between 1996 and 2005 were reviewed. Patient characteristics, clinical presentation, evaluation, staging, treatment, complications and followup were studied. Patients were followed up to assess disease free and overall survival according to the stage of disease and the surgical procedure performed.

Results: 17 patients were treated for AM between 1996 and 2005. At presentation 4 (23%) had metastatic and 1 (6%) had inoperable disease. 12 patients (71%) had operative therapy of which 10 had APER and two had WLE. 82% of these patients were followed up for a mean duration of 8 months (range 3-30 months) and their overall and disease free survival compared. The stage specific disease free and overall survival for patients who underwent APER was 8 months and 13 months for stage I and 7 months and 10 months for stage II respectively. The disease free survival and overall survival for patients who underwent WLE, both for stage I disease, was 10 months and 27 months respectively.

Conclusion: Despite surgical resection and emergence of various forms of adjuvant therapy, the overall prognosis of anorectal melanoma remains dismal. From a review of literature and our own experience, though limited, we conclude that WLE be recommended where negative margins can be achieved and where this is technically feasible. APER should be reserved for large tumours where WLE is not technically possible.