Impact of adjuvant therapies following surgery for anal melanoma.

BACKGROUND: Anal melanoma is rare. Surgery is standard of care for non-metastatic disease. There are limited data supporting adjuvant therapy. We sought to examine the impact of adjuvant radiation, chemotherapy and immunotherapy on survival. METHODS: The National Cancer Database was queried. Factors associated with overall survival were examined by Kaplan-Meier and Cox proportional hazards analyses. Patients were grouped by treatment regimen. RESULTS: 450 patients had complete treatment data: surgery alone (63.8%), surgery + radiation (14.9%), surgery + chemotherapy (7.6%), surgery + immunotherapy (9.6%) and non-surgical treatment (4.2%). Median survival was 27.2 months. Node-positive patients had worse survival than node-negative (22.4 vs. 36.8 months; p = 0.0002). Non-surgical treatment yielded worse survival than any surgery-inclusive regimen (10.4 vs. 27.8 months; p = 0.0002). No adjuvant modality conferred a survival advantage. By multivariate analysis, increasing age (HR/1 year = 1.02, p = 0.012) and node positivity (HR = 2.10, p = 0.0002) negatively impacted survival. CONCLUSION: Adjuvant therapy for non-metastatic anal melanoma does not appear to influence survival.