Factors affecting survival in patients with anal melanoma.

Anal melanoma is an aggressive tumor with a predilection for early infiltration and distant spread, resulting in poor overall survival. Because anal melanoma is rare, only small case series are reported in the literature, making it difficult to draw conclusions about optimal treatment and outcome. The Surveillance, Epidemiology, and End Results database was used to identify patients with anal melanomas from 1973 to 2001. In addition to demographics, disease extent at presentation, treatment administered, overall survival, and survival by decade of diagnosis were collected. A total of 126 patients with a mean age of 69.2 years was diagnosed with anal melanoma. Sixty-one per cent were female. Median follow-up was 22.5 months. Median survival was 10 months for those with distant disease, 13 months for patients with regional spread, and 34 months for patients with local disease (P = 0.0001). Five-year survival was 32 per cent, 17 per cent, and 0 per cent for patients presenting with local, regional, and distant disease, respectively (P = 0.0001). Neither age at diagnosis, operation performed, nor use of radiation significantly affected survival. Anal melanoma remains an uncommon but lethal disease. Extent of disease correlates with overall survival. Survival is improving, but the use and extent of operation are not associated with improved overall survival.