Prognostic Validity of the Eighth Edition of the U.S. Joint Committee on Cancer TNM Staging System for Pancreatic Adenocarcinomas: An Analysis of 214 Patients at a Spanish Center

TL;DR

This study compares the 7th and 8th editions of a cancer staging system for pancreatic cancer, finding that the newer edition better predicts tumor recurrence but not survival.

Contribution

The study evaluates the prognostic validity of the 8th edition AJCC TNM staging system for pancreatic cancer in a real-world patient cohort.

Findings

The 8th edition staging system better predicts disease-free survival and recurrence risk.

The 7th edition remains a stronger predictor of overall survival.

Reclassification between editions altered stage distribution, especially in stage II.

Abstract

Pancreatic cancer is one of the deadliest cancers, and accurate staging systems are essential to predict how the disease will progress and to guide treatment decisions. Over time, the staging system for pancreatic cancer has evolved, particularly between the seventh and eighth editions of the classification used by most specialists. This study evaluates how these two staging systems differ in real-world patients and whether one offers better predictions of disease progression and survival. It also investigates whether the number of affected lymph nodes or their proportion in relation to the total examined could improve prognostic accuracy. Our findings suggest that the new edition offers better categorization for predicting tumor progression but does not significantly improve survival prediction. These insights may help clinicians and researchers to better understand how to refine staging systems and identify high-risk patients more effectively.

Introduction: Accurate staging is essential in pancreatic adenocarcinoma due to its aggressive nature and poor prognosis. The 8th edition of the AJCC TNM staging system introduced changes in tumor size criteria and nodal classification. This study compares the prognostic performance of the 7th and 8th editions in resected patients. Material and Methods: A retrospective analysis was conducted on 214 patients with pancreatic adenocarcinoma who underwent curative surgery. TNM staging was assigned according to both AJCC editions. Kaplan–Meier analysis and multivariate Cox regression, stratified by adjuvant therapy, were used to assess disease-free survival (DFS) and overall survival (OS). Results: The 8th edition TNM staging was significantly associated with lower risk of recurrence, with TNM stages I and II independently predicting better DFS (p < 0.05). In contrast, the 7th edition TNM stage I remained the only independent predictor of OS (HR = 0.376; p = 0.023). Reclassification between editions altered stage distribution, particularly within stage II. Conclusions: The 8th edition improves early recurrence stratification, while the 7th edition retains stronger prognostic value for overall survival. Both systems offer complementary insights, supporting outcome-specific staging use.

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