A prognostic nomogram based on lymph node skipping metastases in esophageal squamous cell carcinoma

At present, the definition of lymph node skipping metastases (NSM) in esophageal squamous cell carcinoma (ESCC) is not uniform, and there were few clinical prognostic models with NSM as a factor. On the other hand, N-staging of ESCC has long been controversial. This study aimed to define NSM in ESCC and investigate its prognostic implications. Meanwhile, according to the cumulative number of cervical, thoracic and abdominal region lymph nodes, a new N-stage was defined and compared with the N-stage of American Joint Committee on Cancer/the Union for International Cancer Control (AJCC/UICC) and Japan Esophageal Society (JES).

ESCC patients who underwent radical esophagectomy with lymph node metastases (LNM) between January 2012 and December 2022 at Mianyang Central Hospital and West China Hospital of Sichuan University. Patients were grouped into training and external validation cohorts. NSM was defined as any LNM outside the primary tumor region. Meanwhile, this study created a new postoperative pathology N-staging [PN(n)] based on the regional division of LNM to compare with the 8th edition of the AJCC/UICC and the 11th edition of JES N-staging.

There were 232 patients enrolled (training: 161; validation: 71). Cox-regression identified factors that could predict outcomes independently. Kaplan-Meier survival analysis was performed. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) and calibration plots. Independent risk factors for death included NSM [hazard ratio (HR) =1.5202], age (HR =1.036), T-stage (HR =2.874), and AJCC/UICC N stage (HR =1.9601). Prognostic models for 1-year (AUC: 0.923, 0.985), 3-year (AUC: 0.747, 0.746), and 5-year (AUC: 0.695, 0.713) survival showed high accuracy.

NSM is associated with worse overall survival (OS) in ESCC, and the constructed prognostic model effectively predicts OS for ESCC patients.