235. A NOVEL TUMOR STAGING SYSTEM INCORPORATING CN STATUS FOR STRATIFYING EARLY STAGE ESOPHAGEAL SQUAMOUS CELL CARCINOMA PATIENTS AFTER TRIMODAL THERAPY

Abstract Background This study aims to assess the prognostic significance of cN status in early-stage esophageal squamous cell carcinoma (ESCC) patients following neoadjuvant chemoradiotherapy (nCRT) and develop a novel staging model for personalized survival prediction. Methods Patients with ESCC who underwent nCRT and esophagectomy were included. The Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) were employed to evaluate the validity of various oncological staging systems. A reduction in AIC and BIC values indicates improved predictive capability and accuracy. Results We established a novel staging model by incorporating ypTNM stage and cN status, effectively stratifying ypI ESCC patients. Cox regression analysis showed that only cN status was an independent prognostic factor for both overall survival (p = 0.030) and disease-free survival (p = 0.019) in patients with stage ypI. The newly developed ypTNM-cN staging exhibited a superior alignment with overall survival trends compared to the AJCC 8th ypTNM staging, with a significantly lower AIC of 3143.014 versus 3149.950. This superiority was further supported by a BIC of 3146.605 compared to 3153.541. In terms of disease-free survival outcomes, the emerging ypTNM-cN staging, with AIC and BIC values of 3196.057 and 3199.648, respectively, outperformed the AJCC 8th ypTNM staging, which recorded values of 3203.853 and 3207.444. Conclusion We have devised a novel staging system based on ypTNM stage and cN status to accurately categorize patients with ypI stage. Our ypTNM-cN staging system offers valuable insights into the classification of ypI ESCC and demonstrates reliable classification efficacy for all ESCC patients following nCRT and surgery.