Background:

Gastric cancer is the fifth most common and a leading cause of cancer death. Since 2005, perioperative chemotherapy (CT) has been the standard for non-metastatic gastric adenocarcinomas. Tumor response relies essentially on histological criteria.

Aims:

The aim of the study was to evaluate tumor regression grade (TRG) after neoadjuvant CT and compare the Mandard and Becker scoring systems.

Methods:

This 15-year retrospective study included patients with gastric adenocarcinoma treated with neoadjuvant CT and surgery. The TRG was assessed using Mandard and Becker scores, evaluated by area under the curve (AUC) for homogeneity, monotonicity, and discrimination. Tumors were staged by the American Joint Committee on Cancer and classified as the World Health Organization.

Results:

Forty patients (mean age 62 years; M:F ratio 2.6) were included. Tubular adenocarcinoma was the most common (48%), and 20% were stage IV. Mandard TRG1 and TRG5 each accounted for 15%, with median survivals of 48 and 30.5 months, respectively. For Becker TRG, they were 25.15 months (TRG 1), 24 months (TRG 2), and 54 months (TRG 3). The mean survival was 49.2 months for TRG1 and 39.2 months for TRG5 (Mandard), 50.3 months for TRG1 and 42.2 months for TRG3 (Becker). The positive predictive values for Mandard and Becker were 1.116 and 0.418 at 1 year and 5.719 and 1.820 at 5 years. The linearity values for Mandard and Becker were 0.6 and 0.3 at 1 year and 2.5 and 2.2 at 5 years. The AUC values at 1 year were 0.568 (Mandard), and 0.545 (Becker), and 0.606 for both at 5 years.

Conclusions:

TRG is an independent survival predictor in gastric cancer, with similar performance between Mandard and Becker scores. Combined with ypTNM staging, it may enhance prognostic accuracy.