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

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.

To evaluate the association between reduced tumor staging after neoadjuvant therapy and lymph node involvement in patients with gastric adenocarcinoma.

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.

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).

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.