The Impact of Gastric Anatomical Subdivisions on the Response to Neoadjuvant Chemotherapy in Gastric Cancer.

Abstract

Background: Response to neoadjuvant chemotherapy (NACT) in locally advanced gastric cancer varies. This study compares tumor response to NACT across anatomical locations, considering clinicopathological differences.

Materials and methods: This retrospective study included 212 patients with gastric adenocarcinoma who received NACT followed by surgery. Tumors were classified by location (antrum-pylorus, corpus-fundus, cardia). Treatment response was assessed using the Modified Ryan Scoring System (0 = complete, 1 = near complete, 2 = partial, 3 = minimal/none).

Results: Tumor locations were antrum-pylorus (30.2%), corpus-fundus (28.3%), and cardia (41.5%). Localization showed no statistically significant differences in response (p = 0.337). However, cardia tumors were more frequent in Groups 3 (40.9%) and 4 (48.1%), which showed poorer pathological responses, whereas antrum (34.6%) and corpus (38.5%) tumors were more common in Group 1, representing patients with a pathological complete response. These findings suggest that cardia tumors may have a lower response to NACT, although definitive conclusions cannot be drawn. In multivariate analysis, only advanced T stage (T3-4) was independently associated with poor tumor regression grade response (odds ratio 14.3, 95% confidence interval 5.4-37.5, p < 0.001).

Conclusions: Tumor response to NACT varied by anatomical location, although differences were not statistically significant. Cardia tumors showed a trend toward lower response rates. To the authors' knowledge, this is the first study evaluating gastric anatomical subgroups in this context. While not conclusive, the findings suggest that tumor location may influence treatment strategies, warranting validation in larger studies.