Establishment and validation of a nomogram for predicting overall survival of node-negative perihilar cholangiocarcinoma.

AIM There lacks a predictive model for overall survival (OS) of node-negative perihilar cholangiocarcinoma (PHC). This study aimed at developing and validating a prognostic nomogram to predict OS of node-negative PHC after resection. METHODS We established a nomogram via multivariate regression analysis by using the design cohort (n = 410, obtained from Surveillance, Epidemiology, and End Results database), and its external verification was done in the validation cohort (n = 100, the First Affiliated Hospital of Sun Yat-sen University). Predictive accuracy of the nomogram was assessed by concordance-index (C-index), calibration curves, and decision curve analysis (DCA). Performance of the nomogram was compared with the American Joint Committee on Cancer (AJCC) staging system. RESULTS Multivariate regression analysis revealed that age, tumor grade, and the count of examined lymph nodes were independent prognostic factors for OS of node-negative PHC. The nomogram had a C-index of 0.603 and 0.626 in design cohort and validation cohort, respectively, which was better than that of AJCC staging system (both p < 0.05). The calibration curves showed good consistency between actual and nomogram-predicted OS probabilities. DCA showed that nomogram had better clinical usefulness. Furthermore, the nomogram-predicted scores could stratify the patients into three risk groups, and patients in higher risk group had worse prognosis than those in lower risk group (all p < 0.05). CONCLUSION The proposed nomogram had a better prognostic accuracy than the AJCC staging system in predicting postoperative OS of node-negative PHC. It was helpful to guide the adjuvant therapeutic strategies for node-negative PHC.