Retrospective Cohort Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Dec 15, 2021; 13(12): 2161-2179
Published online Dec 15, 2021. doi: 10.4251/wjgo.v13.i12.2161
Comparison of tumor regression grading systems for locally advanced gastric adenocarcinoma after neoadjuvant chemotherapy
Zi-Ning Liu, Yin-Kui Wang, Li Zhang, Yong-Ning Jia, Shan Fei, Xiang-Ji Ying, Yan Zhang, Shuang-Xi Li, Yu Sun, Zi-Yu Li, Jia-Fu Ji
Zi-Ning Liu, Yin-Kui Wang, Yong-Ning Jia, Shan Fei, Xiang-Ji Ying, Yan Zhang, Shuang-Xi Li, Zi-Yu Li, Jia-Fu Ji, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Gastrointestinal Cancer Center, Peking University Cancer Hospital and Institute, Beijing 100142, China
Li Zhang, Yu Sun, Department of Pathology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital and Institute, Beijing 100142, China
Author contributions: Liu ZN, Wang YK and Li ZY designed this study; Wang YK and Liu ZN enrolled patients and collected clinical data; Zhang L and Sun Y reviewed the samples; Liu ZN and Ying XJ conducted statistical analysis; Liu ZN is responsible for data visualization; Liu ZN and Wang YK drafted this article; All authors read and approved the final manuscript; Liu ZN, Wang YK and Zhang L contributed equally to this work.
Supported by the Beijing Municipal Health Commission, No. DFL20181103 and No. ZYLX201701.
Institutional review board statement: The Ethics Committee of Peking University Cancer Hospital approved this study. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions. Informed consents were obtained from all patients for being included in the study. This study does not involve animal study.
Informed consent statement: All study participants or their legal guardian provided informed written consent about personal and medical data collection prior to study enrolment.
Conflict-of-interest statement: All authors declare no conflict of interest.
Data sharing statement: The datasets during and/or analyzed during the current study are available from the corresponding author on reasonable request.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Zi-Yu Li, MD, PhD, Professor, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Gastrointestinal Cancer Center, Peking University Cancer Hospital and Institute, No. 52 Fucheng Road, Haidian District, Beijing 100142, China. ziyu_li@hsc.pku.edu.cn
Received: May 12, 2021
Peer-review started: May 12, 2021
First decision: July 14, 2021
Revised: July 25, 2021
Accepted: September 15, 2021
Article in press: September 15, 2021
Published online: December 15, 2021
Abstract
BACKGROUND

Current tumor regression grade (TRG) evaluations are based on various systems which brings confusion for oncologists and pathologists when interpreting results. The recent six-tier system (JGCA2017-TRG) recommended by the Japanese Gastric Cancer Association (JGCA) is worth investigating, as four-tier TRG systems are favored in various parts of the world.

AIM

To compare the predictive accuracies of five published TRG systems.

METHODS

Data were retrospectively collected from patients with locally advanced gastric cancer (LAGC) who underwent neoadjuvant chemotherapy followed by D2 Lymphadenectomy between January 2005 and January 2014 at our institution. Outcomes were overall survival (OS) and disease-free survival (DFS), which were evaluated separately using the following TRG systems: JGCA2017, JGCA, Becker, AJCC/CAP, and Mandard.

RESULTS

All five published TRG systems were independent predictors for OS and DFS. Concordance indices of the JGCA2017, JGCA, Becker, AJCC/CAP-TRG, and Mandard systems were 0.651/0.648 0.652/0.649, 0.693/0.695, 0.688/0.685, and 0.674/0.675 for OS and DFS, respectively. The four-tier Becker system showed the highest c-index, which was significantly greater than that of the six-tier JGCA2017 and five-tier JGCA systems (P < 0.05 in OS and DFS). When residual tumor percentages were reset as: “no residual tumor”, < 10%, < 100%, and “no response”, the rearranged cutoff values achieved a maximum c-index with 0.728 for OS and 0.737 for DFS, which was superior to the other five systems.

CONCLUSION

The newly introduced six-tier JGCA-TRG system cannot increase prognostic stratification. The four-tier Becker system is more suitable for LAGC patients. A population-based study is warranted to define the optimal criterion for TRG in LAGC patients.

Keywords: Gastric cancer, Neoadjuvant chemotherapy, Tumor regression grade, Survival, Concordance index

Core Tip: Current Tumor regression grade (TRG) evaluations are based on various systems bringing confusion to oncologists and pathologists when interpreting results in similar clinical contexts. On the other hand, the recent six-tier system tumor regression grade (JGCA2017-TRG) recommended by Japanese Gastric Cancer Association (JGCA) is investigational. This is the first report of the use of the c-index to evaluate predictive accuracies of five published TRG systems in gastric cancer. With a satisfying sample size, our results gave clinicians a better understanding of the TRG, especially the residual tumor percentage, in gastric cancer and furthermore alleviates the oncologists and pathologist’s workload.