Factors Associated With Host Immune Response and Number of Lymph Nodes: A Large Retrospective Cohort Study

Background: The host immune response (HIR) against tumor cells is one of the key players in antitumor activities. However, the relationship between HIR and regional lymph nodes (LN) and their impacts on prognosis have not been studied. Methods: This study analyzed HIR and clinicopathologic factors for 8819 consecutive gastric cancer patients who underwent gastrectomy and D2 LN dissection. The findings confirmed Epstein–Barr virus (EBV) with Epstein–Barr encoding region in situ hybridization, HIR grading (G1, G2, and G3), LN numbers classified into seven groups, and performed ordinal regression analysis. Results: The mean number of LNs was 41. A higher degree of HIR was significantly associated with male sex, EBV+, non-intestinal histology by Lauren classification, earlier American Joint Committee on Cancer (AJCC) stage, and greater number of LNs (P < 0.001). Female gender, younger age (< 60 years), EBV+, non-intestinal histology, higher HIR grade (G2 and G3), larger tumor size, and deeper invasion depth were significantly related to a higher number of LNs, with an odds ratio greater than 1. In cancer-specific survival analyses, EBV+, younger age, higher HIR grade (G3), and increased number of LNs were independent prognostic factors in addition to AJCC stage. Conclusions: The HIR was associated with increased number of LNs was a significant favorable prognosticator.