Feasibility of Regional Lymphadenectomy for Stomach-Preserving Surgery in Early Gastric Cancer Omitting Sentinel Node Navigation: A Post Hoc Analysis of the SENORITA Trial

Background: Sentinel node navigation (SNN) has been known as the effective treatment for stomach-preserving surgery in early gastric cancer; however, SNN presents several technical difficulties in real practice. Objective: This study aimed to evaluate the feasibility of regional lymphadenectomy omitting SNN, using the post hoc analysis of a randomized controlled trial. Methods: Using data from the SENORITA trial that compared laparoscopic standard gastrectomy with lymphadenectomy and laparoscopic SNN, 237 patients who underwent SNN were included in this study. Tumor location was divided into longitudinal and circumferential directions. According to the location of the tumor, the presence or absence of lymph node (LN) metastases between sentinel and non-sentinel basins were analyzed. Proposed regional LN stations were defined as the closest area to the primary tumor. Sensitivities, specificities, positive predictive values, and negative predictive values (NPV) of SNN and regional lymphadenectomy were compared. Results: Metastasis to non-sentinel basins with tumor-free in sentinel basins was observed in one patient (0.4%). The rate of LN metastasis to non-regional LN stations without regional LN metastasis was 2.5% (6/237). The sensitivity and NPV of SNN were found to be significantly higher than those of regional lymphadenectomy (96.8% vs. 80.6% [p = 0.016] and 99.5% vs. 97.2% [p = 0.021], respectively). Conclusions: This study showed that regional lymphadenectomy for stomach-preserving surgery, omitting SNN, was insufficient; therefore, SNN is required in stomach-preserving surgery.