Impact of lymph node dissection on survival outcomes in gastric cancer patients receiving immune checkpoint inhibitors

The role of lymph node dissection in gastric cancer (GC) patients undergoing immune checkpoint inhibitor (ICI) therapy remains unclear. While extensive lymph node dissection has been a cornerstone of GC surgery, its impact on the efficacy of ICIs, which rely on immune functionality, warrants investigation. This retrospective study analyzed 218 GC patients treated with ICIs and compared their outcomes based on the number of lymph nodes dissected. Propensity score matching and multivariate Cox regression analyses were conducted to minimize confounding factors and identify independent prognostic variables. Subgroup analyses were performed based on lymph node metastasis status to explore potential interactions. Patients with fewer lymph node dissections demonstrated significantly longer progression-free survival (χ 2 = 4.714, P = .030) and overall survival (χ 2 = 5.826, P = .009) compared to those with extensive dissections. Subgroup analyses revealed that this association persisted in patients with positive lymph node metastasis but was less evident in those without metastasis, likely due to group imbalance. Propensity score matching analysis further supported the association between fewer lymph node dissections and improved survival outcomes. However, multivariate analysis indicated that the number of lymph nodes dissected was not an independent prognostic factor. This study revealed that a lower number of lymph node dissections is associated with improved recurrence-free survival and overall survival in GC patients receiving ICIs, suggesting a potential benefit of preserving immune-active lymph nodes.