Influence of lymphadenectomy extent on the efficacy of immunotherapy in recurrent gastric cancer patients

Abstract

Background: Current guidelines recommend ≥16 lymph node (LN) dissection for gastric cancer, preferably >30. However, optimal LN count for immunotherapy after recurrence remains unclear.

Methods: Retrospective study of 147 gastric adenocarcinoma patients receiving immunotherapy for postoperative recurrence (2017-2023). Participants were grouped by dissected LN (DLN) count. Outcomes included progression-free survival (PFS), overall survival (OS), and objective response rate (ORR).

Results: We collected data from 147 patients and stratified them into three groups by DLN count. Stratification revealed: Group A (DLN≤15, 6.1 %, n = 9), Group B (16-30, 44.2 %, n = 65), and Group C (>30, 49.7 %, n = 73). The median disease-free survival (DFS) post-initial surgery was 19.0 months. PFS under immunotherapy differed significantly: Group A (6.0 months) had worse outcomes than B (8.0 months), while C showed intermediate results (7.0 months; P = 0.017). OS followed a similar trend, with Group B having the longest median survival (18.0 months vs. 14.0 for A and 13.0 for C; P = 0.223). ORR was 34.0 %, with progressive disease (PD) more frequent in Group C (30.1 % vs. 20.0 % in B; P = 0.244). Multivariate analysis confirmed DLN count as the sole independent predictor of outcomes.

Conclusion: DLN count exhibits a U-shaped association with immunotherapy efficacy: both insufficient (≤15) and excessive (>30) dissection correlate with poorer PFS/OS versus moderate resection (16-30). Inadequate lymphadenectomy may cause stage migration, while excessive dissection could disrupt antitumor immunity. Precision lymphadenectomy balancing oncologic radicality and immune preservation is advocated.

Keywords: Dissected lymph node count; Gastric cancer; Immunotherapy; Lymphadenectomy; Recurrence.