Controlling nutritional status score as a prognostic marker to predict overall survival in resected biliary tract cancers.

Background: The aim of our study was to explore the prognostic significance of the preoperative controlling nutritional status (CONUT) score and establish a nomogram to predict overall survival (OS) and to achieve a more accurate prognostic risk stratification.

Methods: Clinicopathological records of 371 patients who underwent surgical resection for biliary tract cancers (BTC) from December 2002 to December 2017 were reviewed retrospectively. The associations of the CONUT score with clinicopathological factors and OS were evaluated. Univariate and multivariable Cox regression analysis were used to screen out independent predictors. A nomogram was developed and validated to estimate OS.

Results: The CONUT score was an independent predictor of OS [hazard ratio 1.478, 95% confidence interval (CI), 1.078-2.025, P=0.015]. And patients with a high CONUT score tended to have a poor prognosis with poor differentiation (P=0.011) of tumor cells and longer hospital stays (P=0.046). Besides the CONUT score, carbohydrate antigen 19-9, surgical method, and the American Joint Committee on Cancer (AJCC; 7th edition) TNM stage were contained in the final prognostic model. An OS nomogram was generated to visually predict 1-, 3-, and 5-year OS. The C-index was 0.714 (95% CI, 0.673-0.755) and 0.679 (95% CI, 0.616-0.742) in the development and validation cohort respectively. The nomogram provided superior discriminative power than the AJCC TNM staging system. The nomogram also demonstrated good risk stratification power in the entire cohort of BTC patients as well as for both BTC and surgical method subgroups.

Conclusions: The nomogram based on the CONUT score can predict OS in patients with BTCs, and it performed better than the AJCC TNM staging system.