Assessment of the external validity of the American Joint Committee on Cancer 8th staging system for anal carcinoma

AbstractBackground: The current study evaluates the prognostic value of the 8th edition of the American Joint Committee on Cancer (AJCC) staging system for patients with anal carcinoma.Patients and methods: The Surveillance, Epidemiology and End Results (SEER) database (2004–2014) was explored and AJCC 6th and 8th stages were formulated. Through Kaplan–Meier analysis, overall survival analyses were performed. The Cox regression model (adjusted for age, gender, histology, ethnicity, subsite and grade) was calculated for cancer-specific survival and, subsequently, pairwise comparisons of hazard ratios were calculated.Results: A total of 11,934 anal carcinoma patients were included in the analysis. Overall survival was compared according to both AJCC 6th and 8th systems. For both staging systems, the p value for the trend in overall survival was significant (p < .0001). Nevertheless, for the AJCC 6th system, stage IIIA and IIIB curves were overlapping; while for the AJCC 8th system, the median survival for s...