Background: Anal melanoma is a rare disease with a poor prognosis. Limited data are available regarding oncologic outcomes during the last decade and surgical practice patterns. This study aimed to investigate survival and operative oncologic outcomes for patients with anal melanoma.
Methods: The National Cancer Database (2004-2013) was used to identify patients with nonmetastatic anal melanoma who underwent surgical treatment. The primary outcome was overall survival.
Results: The study enrolled 439 patients in the local excision group and 214 patients in the abdominoperineal resection (APR) group. The patients in the APR group were older (70 vs 65 years; p < 0.001) and had larger tumors (40 vs 25 mm; p < 0.001). After resection, the APR patients were more likely to have positive lymph nodes (65.7% vs 12.5%; p < 0.001) and less likely to have positive margins (10% vs 29.8%; p < 0.001). Overall survival did not differ significantly between the APR and local excision patients (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.67-1.01; p = 0.06). The patients undergoing local excision showed was a significant survival advantage for those with negative margins (HR, 0.70, 95% CI, 0.53-0.93; p = 0.009). Among the patients undergoing APR, a significant survival advantage was observed for those with negative nodes (HR, 0.50; 95% CI, 0.35-0.69; p = 0.002) and negative margins (HR, 0.34; 95% CI, 0.15-0.77; p < 0.001).
Conclusions: The overall survival of anal melanoma patients is similar after local excision and APR. Patients with positive margins, positive lymph nodes, or both have a significantly decreased overall survival.