Published online Dec 15, 2021. doi: 10.4251/wjgo.v13.i12.2161
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
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.
To compare the predictive accuracies of five published TRG systems.
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.
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 respon
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.
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.