Proposed modifications of supraclavicular lymph node metastasis in the esophageal squamous cell carcinoma staging system for improved survival stratification

Abstract

The present study aims to investigate the clinical implication of supraclavicular lymph nodes (SCLNs) in thoracic esophageal squamous cell carcinoma (ESCC). A total of 1156 ESCC patients who underwent three-field lymphadenectomy with node metastasis were analyzed retrospectively. SCLNs were defined as regional nodes in the current system or as distant nodes in the modified system. Survival was analyzed using the Kaplan-Meier method, and values were compared using the log-rank test. Multivariate analysis was performed using the Cox proportional hazard model. The Akaike information criterion (AIC) and the concordance index (c-index) were applied to compare the two prognostic systems. Among 1156 patients, 183 (15.8%) patients were diagnosed with SCLN metastasis. Higher rate of SCLN metastasis was associated with upper tumor location, metastasis involving seven or more nodes, and positive recurrent laryngeal nerve node status. The current staging system was unable to stratify overall survival well in patients with N2, N3, and M1 status using a univariate analysis. In both the current staging system and the modified version, age, gender, pathological T status, and nodal status were independent prognostic factors in a multivariate analysis. The AIC value for the modified version was smaller than that for the current staging system; the c-index value for the modified version was larger than that for the current staging system. Based on the data from our single center, SCLNs should be reclassified as regional lymph nodes in thoracic ESCC for better stratification of overall survival.