Original Article/Pancreas
Evaluation of the 8th AJCC staging system for pathologically versus clinically staged pancreatic adenocarcinoma: A time to revisit a dogma?

https://doi.org/10.1016/j.hbpd.2018.01.014Get rights and content

Abstract

Background

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for pancreatic exocrine adenocarcinoma has been released. The current study seeks to assess the 7th and 8th editions among patients registered within the surveillance, epidemiology and end results (SEER) database.

Methods

SEER database (2010–2013) has been accessed through SEER*Stat program and AJCC 8th edition stages were reconstructed utilizing the collaborative stage descriptions. Kaplan–Meier analysis of overall survival and pancreatic cancer-specific survival analyses (according to both 7th and 8th editions and according to whether pathological or clinical staging were conducted) has been performed. Multivariate analysis of factors affecting pancreatic cancer-specific survival was also conducted through a Cox proportional hazard model.

Results

A total of 18  948 patients with pancreatic adenocarcinoma were identified in the period from 2010–2013. Pancreatic cancer-specific survival among pathologically staged patients and according to the 8th edition showed significant differences for all pair wise comparisons among different stages (P < 0.0001) except for the comparison between stage IA and stage IB (P = 0.307) and the comparison between stage IB and stage IIA (P = 0.116). Moreover, P value for stage IA vs IIA was 0.014; while pancreatic cancer-specific survival according to the 7th edition among pathologically staged patients showed significant differences for all pair wise comparisons among different stages (P < 0.0001) except for the comparison between IA and IB (P = 0.072), the comparison between stage IIA and stage IIB (P = 0.065), the comparison between stage IIA and stage III (P = 0.059) and the comparison between IIB and III (P = 0.595). Among clinically staged patients (i.e. those who did not undergo initial radical surgery), the prognostic performance of both 7th and 8th stages for both overall survival and pancreatic cancer-specific survival was limited.

Conclusion

There is clearly a need to have two staging systems for pancreatic adenocarcinoma: pathological and clinical staging systems.

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.

References (22)

  • ChenYT et al.

    Equipping the American Joint Committee on Cancer staging for resectable pancreatic ductal adenocarcinoma with tumor grade: a recursive partitioning analysis

    Med Oncol

    (2016)
  • T Schnelldorfer et al.

    Staging laparoscopy in pancreatic cancer: a potential role for advanced laparoscopic techniques

    J Am Coll Surg

    (2014)
  • MaJ et al.

    The rise and fall of cancer mortality in the USA: why does pancreatic cancer not follow the trend?

    Future Oncol

    (2013)
  • EP Simard et al.

    Cancers with increasing incidence trends in the United States: 1999 through 2008

    CA Cancer J Clin

    (2012)
  • W Steen et al.

    Prognostic value of occult tumor cells obtained by peritoneal lavage in patients with resectable pancreatic cancer and no ascites: a systematic review

    J Surg Oncol

    (2016)
  • ChenY et al.

    Long-term results of intraoperative electron beam radiation therapy for nonmetastatic locally advanced pancreatic cancer: retrospective cohort study, 7-year experience with 247 patients at the National Cancer Center in China

    Medicine (Baltimore)

    (2016)
  • AM Varghese et al.

    Current management and future directions in metastatic pancreatic adenocarcinoma

    Cancer

    (2016)
  • E Sirri et al.

    Recent trends in survival of patients with pancreatic cancer in Germany and the United States

    Pancreas

    (2016)
  • A Deeb et al.

    Pulmonary metastases in pancreatic cancer, is there a survival influence?

    J Gastrointest Oncol

    (2015)
  • J Lemke et al.

    Brain metastasis in pancreatic cancer

    Int J Mol Sci

    (2013)
  • A Kumar et al.

    CNS involvement in pancreatic adenocarcinoma: a report of eight cases from the Johns Hopkins Hospital and review of literature

    J Gastrointest Cancer

    (2015)
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    • Evaluation of the prognostic value of the new AJCC 8th edition staging system for patients with pancreatic adenocarcinoma; a need to subclassify stage III?

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