Assessment of the 8th Edition of the AJCC TNM Staging System in Cohort With Resected Pancreatic Cancer
In a study reported in JAMA Surgery, van Roessel et al found that the recently released 8th edition of the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system for pancreatic cancer provided better distribution among cases and some increase in prognostic accuracy vs the 7th edition among an international cohort of patients with resected pancreatic ductal adenocarcinoma.
The study included 1,525 patients from Europe and the United States from 2000 to 2015. Patients had undergone pancreatoduodenectomy for nonmetastatic pancreatic ductal adenocarcinoma. Patients were retrospectively staged according to the 7th and 8th editions of the TNM staging system. The median age was 66 years, and 53% of patients were male.
Staging Changes and Prognostic Accuracy
For the 7th vs 8th edition, the distribution among stages was IA in 2.7% vs 7.7%, stage IB in 2.8% vs 9.4%, stage IIA in 13.1% vs 1.4%, stage IIB in 80.6% vs 42.2%, and stage III in 0.8% vs 39.2%. With use of the 8th edition, 774 patients (50.8%) migrated to a different stage, with 183 (12.0%) being reclassified to a lower stage and 591 (38.8%) to a higher stage.
Median overall survival for the entire cohort was 24.4 months. On Kaplan-Meier analysis, 5-year survival rates changed from 38.2% for stage IA, 34.7% for IB, 35.3% for IIA, 16.5% for IIB, and 0% for stage III (P < .001) with the 7th edition to 39.2% for stage IA, 33.9% for IB, 27.6% for IIA, 21.0% for IIB, and 10.8% for stage III (P < .001) with the 8th edition.
Among node-negative patients (18.6% of cohort), T stage was not discriminatory for survival in either edition. In the 8th edition, the new N staging was highly discriminative for survival, with 5-year survival rates of 35.6% for N0, 20.8% for N1, and 10.9% for N2 (P < .001). For prognostic performance for overall survival, the C statistic improved from 0.55 (95% confidence interval [CI] = 0.53-0.57) for the 7th edition to 0.57 (95% CI = 0.55-0.60) for the 8th edition. Receiver operating characteristic area under the curve values were 0.56 with the 7th editions vs 0.61 for the 8th edition at 3 years after surgery and 0.59 vs 0.65 for 5-year survival.
The investigators concluded, “The 8th edition of the TNM staging system demonstrated a more equal distribution among stages and a modestly increased prognostic accuracy in patients with resected pancreatic ductal adenocarcinoma compared with the 7th edition. The revised T stage remains poorly associated with survival, whereas the revised N stage is highly prognostic.”
The study was supported by the National Institutes of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.
Marc G. Besselink, MD, PhD, of the Department of Surgery, University of Amsterdam, Amsterdam UMC, is the corresponding author for the JAMA Surgery article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
