Prognostic value of different tumor regression grade systems for patients with locally advanced gastric cancer receiving neoadjuvant therapy

Objective To explore the relationship between different tumor regression grade systems(ypTNM stage, Mandard-TRG grade, Becker-TRG grade, and JGCA-TRG grade) and clinicopathological characteristics of patients with locally advanced gastric cancer after receiving neoadjuvant therapy, and compare the prognostic value of these systems.

Methods 198 patients with locally advanced gastric cancer who received neoadjuvant therapy followed by radical gastrectomy in Zhongshan Hospital, Fudan University from January 2014 to December 2019 were retrospectively collected. Postoperative tissue samples were re-evaluated according to AJCC 8th ypTNM stage, Mandard-TRG, Becker-TRG, and JGCA-TRG. Relationships between various tumor regression grade systems and clinicopathological characteristics and the prognostic value of these systems were analyzed.

Results A total of 198 patients with locally advanced gastric cancer who received neoadjuvant therapy were included, of whom 152 were male and 46 were female. The composition ratios of tumour size, ypT, ypN, vascular infiltration, and nerve invasion were statistically different among different tumor regression grades classified by three TRG criteria. Kaplan-Meier analysis showed statistically significant differences in OS between different Becker grades or JGCA grades (P＝0.019, P＝0.035), while the differences in OS between different Mandard grades were not significant (P＝0.146). Further comparing the survival of Becker 1a-2 and Becker 3 patients, the prognosis of Becker 1a-2 patients was significantly better than that of Becker 3 patients (P＝0.002), and the prognosis of JGCA 2-3 patients was also significantly better than that of JGCA 0-1b patients (P＝0.006). Cox regression analysis showed that none of the three tumor regression grades was an independent prognostic factor for patients with gastric cancer receiving neoadjuvant therapy. The area under ROC curves (AUC) of three TRG systems to predict the 5 year OS was 0.608, 0.624 and 0.611.

Conclusion Becker-TRG have a slightly better prognostic value than JGCA-TRG and Mandard-TRG for gastric cancer patients receiving neoadjuvant therapy, but there is still an urgent need to explore more comprehensive and precise criteria for pathological evaluation of gastric cancer after neoadjuvant therapy.