SRRN: A regional lymph node ratio-based staging system enhancing prognostic accuracy in esophageal squamous cell carcinoma

Abstract

Background: Esophageal squamous cell carcinoma (ESCC) carries a poor prognosis, with lymph node status being a critical determinant. Traditional N staging and the lymph node ratio (LNR), which rely solely on the number of positive lymph nodes, may lack precision. This study proposes a novel staging system based on the sum of regional lymph node ratios (SRRN) to enhance prognostic assessment.

Methods: In this single-center, retrospective cohort study, we retrospectively analyzed 1208 ESCC patients who underwent radical resection at Fujian Medical University Union Hospital between 2010 and 2020. The regional lymph node ratio (RLNR) was calculated for each lymph node station and summed to define SRRN. Patients were stratified into SRRN0-3 groups using X-tile. The prognostic value of SRRN versus traditional N staging was evaluated using Cox regression and random survival forest (RSF) models, while survival differences among groups were compared via Kaplan-Meier analysis.

Results: SRRN emerged as an independent predictor of overall survival (OS). Compared to N staging, SRRN demonstrated superior predictive performance in both Cox and RSF models, with higher AUC and C-index values. Kaplan-Meier curves revealed more pronounced survival differences among SRRN groups. Kaplan-Meier curves revealed substantially greater prognostic separation among SRRN groups, with 5-year OS rates of 66.7 % for SRRN0 compared to only 7.9 % for SRRN3. Nomograms incorporating SRRN showed good calibration and potential clinical utility.

Conclusion: The SRRN staging system outperforms traditional N staging in prognostic stratification and may guide optimized staging and individualized treatment decisions for patients with ESCC.

Keywords: Esophageal squamous cell carcinoma(ESCC); Prognosis; Regional lymph node ratio (RLNR); SRRN staging system.