Anorectal malignant melanoma

Background: Great controversy exists with regard to the best surgical therapy for anorectal malignant melanoma. Materials and Methods: Between 1980 and 1996, 15 patients with anorectal malignant melanoma were treated. The recurrence pattern after therapeutic intervention and their survival were evaluated. Results: There were nine females and six males, their mean age was 66.3 years. At diagnosis their disease stages were: I (n = 7), II (n = 3) and III (n = 5). Patients with stage disease were treated with abdominoperineal resection (APR) (n = 6) and local excision (n = 1); their average tumour size and thickness were: 4.7 cm and 6.4 mm respectively; their median follow-up and disease-free survival were 11 months and 7 months respectively; their recurrence pattern was: local (n = 6), inguinal (n = 4) and distant (n = 6). Those patients with stage II and III disease were treated with transverse colostomy (n = 6); two of them received 50 Gy of radiotherapy and local excision plus interferon alpha-2b (n = 2), all had progressive distant disease. Patients with stage I disease had a median survival of 12 months compared with 5 months for those with stages II and III (P = 0.10). The overall 5-year survival was 0%. Conclusion: The recurrence pattern in anorectal malignant melanoma is mainly at distant sites. The role of APR in maintaining local control over tumours larger than 4 cm or thicker than 5 mm remains elusive.