Station-Specific Lymph Node Metastasis After Neoadjuvant Chemoimmunotherapy for Middle Thoracic Esophageal Squamous Cell Carcinoma

Neoadjuvant chemoimmunotherapy (NCIT) is increasingly used for locally advanced esophageal squamous cell carcinoma (ESCC). However, the station-specific distribution of residual lymph node metastasis after NCIT remains incompletely characterized, and whether a pathologic complete response of the primary tumor implies nodal clearance is unclear. This single-center retrospective cohort study included consecutive patients with middle thoracic ESCC who underwent esophagectomy with lymphadenectomy (at least 15 nodes retrieved) between June 2012 and June 2025. Station-specific lymph node metastasis rates were analyzed in the NCIT group (n = 272) according to residual pathologic T category (ypT), and in the upfront surgery group (n = 445) according to pathologic T category (pT). The two groups followed different clinical pathways and were not randomized; between-group comparisons are descriptive only and no causal inference is intended. The study aims to provide an anatomic basis for surgical planning and postoperative risk stratification in middle thoracic ESCC.