Original Article/PancreasEvaluation of the 8th AJCC staging system for pathologically versus clinically staged pancreatic adenocarcinoma: A time to revisit a dogma?
Introduction
Pancreatic cancer is unfortunately an important cause of cancer-related mortality globally with poor prognosis and limited effective treatment options [1]. Histologically, pancreatic exocrine adenocarcinoma represents the most common as well as the most aggressive pancreatic cancer subtype [2].
Treatment algorithms for pancreatic exocrine adenocarcinoma have been designed according to two landmarks; namely: tumor characteristics (local, regional and distant extent of the disease which is summarized by its stage) and patient characteristics (including performance score, age and concurrent medical conditions) [3]. For medically operable and surgically resectable disease, surgical resection is the mainstay of curative treatment, to be followed or preceded by (neo)adjuvant chemotherapy [4]; for unresectable but non-metastatic disease, different combinations of chemoradiotherapy have been suggested; while for metastatic disease, the primary treatment is systemic treatment [5].
The most common staging system for pancreatic cancer is the Tumor/Node/Metastasis (TNM)/American Joint Committee on Cancer (AJCC) system [6]. The released numerous editions of AJCC staging system tried to reflect advancement in our knowledge of the prognostic factors of pancreatic cancer as well as the changes in therapeutic paradigms of this disease [7], [8], [9]. In the most recent edition of the staging system (8th edition), some relevant changes were described compared to the 7th edition. These include: the separation of exocrine and endocrine tumors into different staging systems, more dependence on size criteria in T staging as well as subdivision of N positive status into N1 and N2 according to the number of positive lymph nodes [10]. Validation of the prognostic performance of these changes among different population-based databases, different clinical scenarios (clinical staging versus pathological/surgical staging) as well as different oncological end points (overall survival versus pancreatic cancer-specific survival) would enlighten the practicing physician into the potentials and limitations of this new system. Moreover, such a validation would ideally highlight knowledge gaps where further changes/improvements in the staging system may be needed. Surveillance, epidemiology and end results (SEER) database is an ideal choice for this validation given its large size, credibility and rigorous quality assurance program.
The objective of this study is to compare the prognostic performance of the 7th and 8th editions of the pancreatic cancer AJCC staging system according to the method of staging (pathologically staged versus clinically staged) in a group of patients registered within the SEER database.
Section snippets
Methods
The study records were extracted from the SEER-18 registry [11]; and in order to accomplish this, SEER*Stat software Version 8.3.2 was utilized.
Patients’ characteristics
A total of 32 369 patients with pancreatic adenocarcinoma were identified in the period from 2010–2013 and were included into the intention to diagnose group. After excluding cases with insufficient information about survival, TNM 7th stage, and tumor size or extension, the total number of cases was 18 948 and they were included into further analyses.
Diagnosis was based on pathology/cytology in 96.8% of cases while it was based on radiology/clinical assessment only in 3.0% of cases. Among
Discussion
The current analysis provided an assessment of the performance of the newly released pancreatic cancer AJCC 8th staging system through an external database. It showed that among pathologically staged patients, there was a modest improvement in prognostic performance for the 8th edition compared to the 7th edition; while among clinically staged patients, the performance of both editions was disappointing.
Looking closely at the Kaplan–Meier curves for pathologically staged patients according to
Contributors
ARO is the sole contributor to this study.
Funding
None.
Ethical approval
Not needed.
Competing interest
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
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Cited by (9)
Evaluation of the prognostic value of the new AJCC 8th edition staging system for patients with pancreatic adenocarcinoma; a need to subclassify stage III?
2018, European Journal of CancerCitation Excerpt :Our single-centre cohort might not have enough power to show the statistical differences in the new T-stage classification among node-negative patients. However, recent validation studies using the SEER database also did not show significant prognostic differences according to the new T stage of AJCC 8th edition [11,17]. Thus, further prospective studies are required to confirm and improve the prognostic value of the new T staging system.