Introduction: Lower mediastinal lymph node dissection has been adopted as standard by treatment guideline for adenocarcinoma of esophagogastric junction(AEJ), but the effect of laparoscopic mediastinal lymph node dissection remains unknown. The aim of this study is to provide standard technical details of laparoscopic mediastinal lymph node dissection, and explore the potential clinical effects, gather key information for following study regarding sample size calculation, primary outcome and feasibility. This study report intervention development, governance procedures and selection and reporting of outcomes to optimize methods for using the Idea, Development, Exploration, Assessment, Long-term follow-up (IDEAL) framework for surgical innovation that informs evidence-based practice.~Methods and analysis: This is an IDEAL stage II, prospective, parallel control, open label, multi-center and exploratory study. The inclusion criteria is Siewert II/ III, AEJ, cT2-4aN0-3M0(AJCC-8th Gastric Cancer TNM stage manual), decide to receive radical gastrectomy, without preoperative anti-neoplastic therapy. The individual included in the study is performed the radical total or proximal gastrectomy plus the lower mediastinal lymphadenectomy via either laparoscopic (trial arm) or open (control arm) TH approach. The surgical approach is determined by the investigator in each center before the operation and recorded in the electronic case report forms (CRF).~The primary outcome is the number of lower mediastinal lymph nodes retrieved. Secondary outcome include complication, surgery length, postoperative death, R0 resection rate, etc. Expected sample size is 518 in each group, thus has 80% power to detect a difference of 0.17 in the average number of lower mediastinal lymph node dissected in between two groups.
Mediastinal lymph node dissection has been adopted as standard treatment for adenocarcinoma of esophagogastric junction(AEJ). This multi-center, exploratory, prospective, cohort study aims at provide standard technical details of laparoscopic mediastinal lymph node dissection, and explore the potential clinical effects, gather key information for following study regarding sample size calculation, primary outcome and feasibility.