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 chol-angiocarcinoma (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 verifi-cation 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. (c) 2021 Asian Surgical Association and Taiwan Robotic Surgery Association. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).