P1.175. Lymph Node Assessment of the Thoracic Duct and Surrounding Compartment in Esophageal Cancer Surgery – the TUPEC Pilot-Study

Abstract

Abstract Topic Esophageal Cancer: Surgical Treatment of Esophageal Cancer Background Standardization of thoracic duct (TD) management during esophageal cancer surgery remains controversial. TD resection has been hypothesized to enhance oncologic radicality, since it may increase the total lymph node yield. This study aims to quantify the lymph node yield of the TD and surrounding compartment in esophageal cancer surgery. Methods This ongoing single-center, prospective pilot study evaluates the lymph node yield of indocyanine green (ICG)-guided TD resection during minimally invasive esophagectomy for esophageal carcinoma (cT1–4aN0–3M0), following neoadjuvant chemo(radio)therapy. The ICG is injected (2ml of 2.5mg/ml) in the small bowel mesenteric root or inguinal lymph node based on the surgical approach – either Ivor-Lewis or McKeown, respectively – before the thoracic phase. Standardized two-field lymphadenectomy is performed according to the TIGER study protocol. The TD and lymph node station 112aoa are processed separately for histopathological evaluation. The primary endpoint is the total lymph node yield in the thoracic duct and surrounding lymphatic compartment. Secondary endpoints include successful ICG-enhanced visualization of the thoracic duct, completeness of resection, procedural safety, and postoperative morbidity. Results Twenty-two of the sixty planned patients were enrolled up to January 2026. No ICG related adverse events occurred. The cohort consisted predominantly of male patients (64%), with a median age of 68 years, and diagnosed with cT3 (64%) and cN0-1 (68%) staged adenocarcinoma (82%). The TD was successfully visually enhanced by ICG-fluorescence in 20/22 patients (91%) and successfully resected in all patients. No viable tumor cells were identified within the resected thoracic ducts. The median resected lymph node yield was 34 [IQR: 24 - 43]. Lymph node station 112aoa contained median 2 lymph nodes [range 0-8], non of which containing tumor cells. The TD contained 0 lymph nodes. Chyle leakage occurred in 4/22 patients (18%) and was managed conservatively in 3 out of 4 cases. Conclusion This study demonstrated a median of two lymph nodes within station 112aoa, whereas no lymph nodes were identified in the thoracic duct itself. Final analyses are anticipated in August 2026. The clinical and oncologic implications of thoracic duct management will be further investigated in the subsequent phase II and phase III TUPEC trial.