Post-neoadjuvant therapy lymph node response in patients with gastric adenocarcinoma

Abstract

ABSTRACT Background: Neoadjuvant chemotherapy is recommended as the standard of care for eligible patients with locally advanced resectable gastric adenocarcinoma. However, given the often-late diagnosis of this tumor, understanding post-neoadjuvant therapy lymph node involvement remains a determining factor in the prognosis of these patients. Aims: To evaluate the association between reduced tumor staging after neoadjuvant therapy and lymph node involvement in patients with gastric adenocarcinoma. Methods: This is a retrospective, analytical, observational study based on the medical records of patients who underwent combination therapy from 2018 to 2024. Pre-treatment clinical staging was performed according to institutional protocol, and the relationship between tumor and lymph node staging was established by comparing the initial clinical staging with the post-treatment pathological staging. Results: Eighty-nine patients were included in the analysis, with a reduction in tumor staging observed in 47.2% of cases, based on pathological T-cell analysis. The mean number of affected lymph nodes was significantly higher in non-responder patients compared to responders (5.0±6.3 versus 1.1±2.2; p<0.001). Simple logistic regression analysis identified that the number of affected lymph nodes was associated with the absence of tumor response in univariate analysis, presenting an odds ratio of 1.317 (95%CI 1.099-1.579; p=0.003). Conclusions: The absence of reduction in tumor staging was associated with a higher residual lymph node burden, highlighting the prognostic relevance of lymph node involvement in post-therapeutic evaluation.