Lymph Node Ratio-Based Nr Staging of Esophageal Squamous Cell Carcinoma: A Large Population-Based Study

This study aimed to investigate the clinical value of lymph node ratio-based Nr staging in esophageal squamous cell carcinoma. Data on 1226 patients with esophageal squamous cell carcinoma between 2004 and 2015 were extracted from the Surveillance, Epidemiology, and End Results database. The Nr staging system was developed based on the lymph node ratio. The lymph node ratio was defined as the number of positive nodes divided by the number of examined nodes. The Cox regression model was used to identify the independent prognostic value of Nr staging. The predictive power of Nr staging and American Joint Committee on Cancer N staging was then compared. Nr staging was used to stratify the patients into four groups with significantly different 5-year survival rates of 52.9%, 43.7%, 23.2%, and 11.5%. Moreover, the Nr staging could stratify patients within each N stage into patients with different prognoses. Multivariable analysis showed that Nr staging was an independent prognostic factor for overall survival, whereas the N staging was not. Nr staging had higher predictive accuracy and clinical utility than the N staging. Compared with N staging, Nr staging had better prognostic predictive power (net reclassification index, 16.9%; 95% confidence interval, 8.6-27.3%). Compared with the traditional N staging, Nr staging can more accurately predict overall survival in patients with esophageal squamous cell carcinoma.