Proposed Modification of the 8th Edition of the AJCC Staging System for Pancreatic Ductal Adenocarcinoma.

OBJECTIVE

The aim of this study was to improve the 8th edition (8th) of the American Joint Committee on Cancer (AJCC) staging system for pancreatic ductal adenocarcinoma (PDAC).

BACKGROUND

The new 8th AJCC staging system for PDAC was released in October, 2016, and will be applied in clinical practice in 2018.

METHODS

Two large cohorts were included in this analysis. One consisted of 45,856 PDAC patients in the Surveillance, Epidemiology, and End Results (SEER) database (2004-2014), and the other consisted of 3166 PDAC patients in the Fudan University Shanghai Cancer Center (FUSCC) database (2005-2015).

RESULTS

Using the 8th AJCC staging system, the median overall survival of the patients in the same stage varied widely among the different substages. We proposed a modified staging system based on median OS in which we maintained the T, N, and M definitions, but regrouped the substages. In the SEER cohort, the concordance index was higher for local disease with the modified staging system [0.637; 95% confidence interval (CI) 0.631-0.642] than with the 8th AJCC staging system (0.620, 95% CI 0.615-0.626). Similar findings were also observed in the FUSCC cohort. In addition, we verified the reliability of the modified staging system in an analysis of patients with different examined lymph node counts (≥15 or 1-14).

CONCLUSIONS

The modified 8th AJCC staging system for PDAC proposed in this study provides improvements and may be evaluated for potential adoption in the next edition.