Sentinel Node Navigation Surgery in Gastric Cancer: A Systematic Review of Diagnostic Test Accuracy and Clinical Outcomes

Background/Objectives: Gastric cancer remains a leading cause of cancer mortality. However, earlier detection has increased the number of cases suitable for organ-preserving treatment. Sentinel node navigation surgery has been proposed as an alternative to standard gastrectomy for early gastric cancer. The safety of this procedure hinges on how accurately sentinel node mapping predicts nodal status. This systematic review synthesizes its diagnostic accuracy and outcome data. Methods: We searched PubMed/MEDLINE, Embase, CENTRAL, the Web of Science Core Collection, and Scopus from inception without date limits, along with two trial registries; screening was restricted to English-language reports. Estimates and exact binomial (Clopper–Pearson) 95% confidence intervals were recalculated from each study’s reported contingency counts using a consistent statistical method. Each included cohort was appraised using QUADAS-2. Results: Eight cohorts contributed per-patient accuracy data, and three contributed per-node molecular comparisons. Detection rates were 97.1% or higher in every cohort entry, with the exception of the naked-eye dye arm of a within-cohort comparison and the smallest feasibility series. Sensitivity was 93.0% (53/57; 95% CI, 83.0–98.1) in the single adequately powered treatment-naive cohort, compared to 69.6% (16/23; 47.1–86.8) in the single prospective trial conducted after non-curative endoscopic resection. Sensitivity also depended on the thoroughness of sentinel node examination: within one cohort, the same patients yielded a sensitivity of 53.6% with single-plane frozen section versus 85.7% with multiple paraffin sections. Therefore, estimates were not pooled. No appraised cohort demonstrated a low risk of bias across all four QUADAS-2 domains. Conclusions: Stomach preservation guided by sentinel node mapping may be a reasonable approach for treatment-naive disease in experienced centers. However, it is not supported after non-curative endoscopic resection.