Optimized modification of the eighth edition of AJCC TNM staging system for resected pancreatic ductal adenocarcinoma.

Aim: To reassess the prognostic performance of the American Joint Committee on Cancer (AJCC) 8th edition for pancreatic ductal adenocarcinoma (PDAC) and optimize the categorization of PDAC staging. Patients & methods: A total of 11,858 patients with resected PDAC from the Surveillance, Epidemiology and End Results database were retrospectively enrolled by sequential analyses. Results: There was no statistical significance between stage IIA and IIB tumors with hazard ratios of 2.065 and 2.184 (p = 0.620) for stages IIA and IIB, respectively. With the proposed modification, there was a significant difference between the hazard ratios of stages IIIA and IIIB which were 2.481 and 2.715, respectively (p = 0.009). The C-index of modified system was 0.609, slightly higher than AJCC 8th staging system 0.604. Conclusion: We proposed a modified eighth edition of the AJCC staging system by combining stage IIA with IIB and further subclassifying stage III patients in order to lead to better discriminative power.