Table_1.pdf

Abstract

Background: The metastatic status of regional lymph node is an effective risk factor for the prognosis of distalcholangiocarcinoma (dCCA). But existing lymph node staging is not accurate enough and is susceptible to interference. This study aims to explore the predictive ability of Log Odds of PositiveLymphNodes (LODDS) stage system of dCCA by comparing with existing lymph nodes stage systems. Methods: Totally 928 dCCA patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database as training cohort and 207 dCCA patients from West China Hospital underwent surgery were reviewed as validation cohort. The least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression were conducted to identify the most meaningful factors relevant to prognosis. The performance of four lymph node stage systems was compared by a model-based approach. Result: Age of diagnosis, pathological grade, American Joint Committee on Cancer(AJCC) tumor 7th T stage, tumor size, radiotherapy, chemotherapy, and lymph node stage system were independent prognostic factors. The model with the LODDS system had a better model fit with the highest C-index (0.679) and 1-/3-/5- area under the receiver operating characteristic curve(AUC) (0.739/0.671/0.658) as well as the lowest Akaike information criterion(AIC) (5020.52). External validation results from 207 dCCA patients showed a C-index of 0.647 and 1-/3-/5-AUC of 0.740/0.683/0.589, respectively. Compared with Lymph node ratio(LNR), AJCC 8th N, 7th N system, the 5-year net reclassification improvement (NRI) of LODDS system was 0.030 [95% confidence intervals (CI): -0.079-0.147] and 0.042 (95%CI: -0.062-0.139) and 0.040 (95%CI: -0.057-0.146), respectively. The integrated discrimination improvement (IDI) of LODDS improved comparing with LNR model (0.016; 95% CI: -0.001-0.036), AJCC8th N system (0.020; 95% CI: 0.003-0.037), AJCC7th N system (0.019; 95% CI: 0.002-0.036). Decision curve analysis (DCA) also shows a greater net benefit of LODDS. In lymph node negative patients, LODDS reveals a positive linear relationship with hazard ratio(HR). The stage capacity of LODDS in subgroup analysis stratified by examined lymph node number (ELNN) was consistent. Conclusions: LODDS lymph node stage system has superior predictive performance compared to LNR, AJCC7th and 8th lymph node stage systems. Meanwhile, LODDS has a more detailed staging ability and good stability.