Purpose: The aim of this study was to validate and improve the 8th edition of the Union for International Cancer Control (UICC) staging system for pancreatic ductal adenocarcinoma (PDAC).
Methods: Prognostic impact of the pathological tumor (pT) and lymph node (pN) stages between the 7th and 8th editions were compared using a single-center cohort of 311 patients who underwent curative pancreatic resection for PDAC.
Results: Applying the 7th edition T staging system resulted in a clustering of pT3 cases (92.3%) and failed to show significant prognostic differences between the three pT stages. However, applying the 8th edition T staging system yielded a more even distribution and resulted in an excellent prognostic separation between the pT stages based on decreases in median survival (month [pT1: 69.4, pT2: 27.6, pT3: 16.7], p=0.001). In pN staging system, the 8th edition provided more precise prognostication in median survival (month [pN0: 41.7, pN1: 25.6, pN2: 14.4], p<0.001). Moreover, in the 8th edition pT2 category, patients with portal vein invasion (PVI) showed significantly worse survival than those without PVI (median survival months [without PVI: 38.2, with PVI: 17.1], p<0.001).
Conclusions: The 8th edition provides a more even distribution among stages and better stage discriminations compared to the 7th edition. The 8th edition pT2 category should be subdivided according to PVI status of the patient to allow for more precise patient prognostication.
Keywords: Pancreatic cancer;; Portal vein invasion;; Staging system;; TNM classification;; Union for International Cancer Control staging system.