P1.168. Lymph Node Metastatic Patterns and Therapeutic Value Index in Esophagogastric Junction Cancer: Esophageal Invasion Length and Neoadjuvant Chemotherapy

Topic Esophageal Cancer: Surgical Treatment of Esophageal Cancer Background The surgical approach and extent of lymph node (LN) dissection for esophagogastric junction (EGJ) carcinoma are stratified by the length of esophageal invasion (EIS); however, inter-institutional variation remains. We investigated LN metastasis patterns, the therapeutic value index (TI), and the impact of neoadjuvant chemotherapy (NAC) to optimize mediastinal LN dissection at our institution. Methods We retrospectively reviewed 111 patients with EGJ carcinoma (adenocarcinoma or squamous cell carcinoma) diagnosed by the Nishi classification who underwent R0/R1 resection between 2010 and 2025. Clinicopathological characteristics and postoperative outcomes were assessed. LN metastasis (LN+) rates and TI were compared by EIS: group A (≤1 cm; n=48), group B (1–3 cm; n=42), and group C (>3 cm; n=21). Among adenocarcinoma patients receiving NAC (n=15), therapeutic effects were categorized as grade 1 (1a+1b) (n=10) versus grade 2-3 (n=5) based on the classification of Japan Esophageal Society (JES). Results Median age was 69 years, and the male-to-female ratio was 91/20. Histology was adenocarcinoma/squamous cell carcinoma in 95/16 patients, and the overall 3-year survival rate was 78%. Pathological stage 0/I/II/III/IV was observed in 1/49/21/31/9 patients. LN stations with a metastatic rate of ≥10% were 106recR, 106recL, 107, 1, 2, 3, 7, 11p, and 19. Upper/middle/lower mediastinal LN+ rates were 0/0/3.4% in group A, 30.8/0/2.7% in group B, and 30.0/20.0/28.6% in group C. Corresponding TI were 0/0/3.4, 23.1/0/2.7, and 15.9/0/17.2, respectively. Among NAC-treated adenocarcinoma patients, upper/middle mediastinal LN+ rate/TI was 42.9% (3/7)/16.7 in the JES Grade 1 group and 0% (0/3)/0 in the JES Grade 2-3 group. In addition, upper/middle mediastinal LN recurrence occurred in 22.2% (2/9) of the JES Grade 1 group and 0% (0/3) of the JES Grade 2-3 group. Conclusion From the standpoint of LN+ rate and TI, upper/middle mediastinal LN dissection may be unnecessary for EIS ≤1 cm but warranted for EIS >3 cm. For EIS 1–3 cm, upper/middle mediastinal dissection may be considered in high-risk disease (cLN+ and/or cT2-4). Omission of upper/middle mediastinal dissection may be an option in patients who respond to NAC. Further accumulation and refinement of indications—including response-based refinement of the extent of lymph node dissection —are needed.