Mesenterico-portal vein invasion should be an important factor in TNM staging for pancreatic ductal adenocarcinoma: Proposed modification of the 8th edition of the American Joint Committee on Cancer staging system

Figure 4 Comparison of the 8^th edition of the American Joint Committee on Cancer staging system and the modified staging system in predicting prognosis. A: Surveillance, Epidemiology, and End Results (SEER) database grouping with the 8th edition American Joint Committee on Cancer (AJCC) stage; B: SEER database grouping with the modified stage; C: West China Hospital database grouping with the 8th edition AJCC stage; D: West China Hospital database grouping with the modified stage. AJCC: American Joint Committee on Cancer; SEER: Surveillance, Epidemiology, and End Results.