AJCC 7th edition staging classification is more applicable than AJCC 8th edition staging classification for invasive...

Area of Science:

• Oncology
• Surgical Pathology
• Cancer Staging

Background:

• The 7th and 8th editions of the American Joint Committee on Cancer (AJCC) staging systems are established for pancreatic adenocarcinoma.
• The clinical utility of these AJCC staging systems for invasive intraductal papillary mucinous neoplasms (IPMN) remains unevaluated.

Purpose of the Study:

• To systematically assess and compare the applicability of the AJCC 7th and 8th edition staging systems for invasive IPMN.
• To determine which AJCC staging edition provides more accurate prognostic information for patients with invasive IPMN.

Main Methods:

• Utilized data from 1216 patients with resected invasive IPMN from the Surveillance, Epidemiology, and End Results (SEER) cancer registry (1973-2014).
• Compared survival rates and performed multivariate analyses using both the AJCC 7th and 8th edition staging classifications.
• Examined differences in stage IIA definitions and the prognostic impact of tumor size in the 8th edition staging system.

Main Results:

• The 7th edition demonstrated a higher hazard ratio for stage IIA compared to stage IB invasive IPMN.
• The 8th edition showed a lower hazard ratio for stage IIA compared to stage IB, and tumor size was not a significant predictor of survival for resectable tumors >2 cm.
• Significant differences were observed in the prognostic stratification between the two AJCC editions for invasive IPMN.

Conclusions:

• The 7th edition AJCC staging classification demonstrates greater applicability and prognostic accuracy for invasive IPMN compared to the 8th edition.
• The 8th edition's revised criteria, particularly regarding tumor size, may not be optimal for stratifying risk in invasive IPMN.
• Further refinement of staging systems may be necessary to accurately reflect the behavior of invasive IPMN.