Practice patterns and outcomes for anorectal melanoma in the USA, reviewing three decades of treatment: is more extensive surgical resection beneficial in all patients?

Introduction: Historically, the treatment of anorectal melanoma has been abdominoperineal resection (APR), but more recently local resection alone. Although treatment at melanoma centers has become less aggressive, the adoption of this approach and related outcomes across the USA is unknown.

Methods: The Surveillance, Epidemiology, and End Results (SEER) database was queried to identify patients treated for anorectal melanoma (1973-2003). Treatment patterns and survival were studied. Frequency of treatment was compared using the chi-square test; survival was calculated using the Kaplan-Meier method.

Results: The 183 patients identified from the SEER database had a median age of 68 years. Of the 143 patients whose data were included, 51 underwent APR and 92 underwent transanal excision (TAE). Despite similar pathologic characteristics, median survival was similar in the two groups: 16 months for APR and 18 months for TAE (P = ns). Five-year survival also was similar in the two groups: 16.8% for APR and 19.3% for TAE (P = ns). The rate of APR was 27.0% between 1973 and 1996, as compared with 43.2% between 1997 and 2003 (P = ns).

Conclusion: This study, the largest series to analyze widespread practice patterns and outcomes for anorectal melanoma in the USA, did not reveal a survival difference comparing TAE with APR. Moreover, the study did not reveal a trend toward less aggressive surgical resection. Since the extent of surgical intervention did not correlate with survival or extent of primary tumor, APR should be reserved for selected patients in whom TAE is not technically feasible.