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), 11 (n=3) and III (n=5). Patients with stage I 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.