This is a multicenter, retrospective observational study using existing medical records of patients with esophageal squamous cell carcinoma who received at least two cycles of neoadjuvant immunochemotherapy followed by curative surgery with complete tumor removal and negative surgical margins between January 2021 and December 2024.
The main aim of this study is to evaluate whether postoperative radiotherapy is associated with better control of cancer recurrence in the surgical area and regional lymph nodes, and whether this association differs according to the extent and number of lymph nodes removed during surgery. Patients will not be assigned to any treatment as part of this study. Outcomes will be compared according to postoperative radiotherapy status and lymph node dissection characteristics.
The primary outcome is locoregional recurrence-free survival. Secondary outcomes include disease-free survival, overall survival, and distant metastasis-free survival. Clinical, surgical, pathological, treatment, and follow-up information will be collected from electronic medical records at six esophageal cancer centers. Approximately 300 patients are expected to be included.