A nomogram based on pretreatment levels of serum bilirubin and total bile acid levels predicts survival in colorectal cancer patients.

ABSTRACT

BACKGROUND: Serum bilirubin and total bile acid (TBA) levels have been reported to be strongly associated with the risk and prognosis of certain cancers. Here, we aimed to investigate the effects of pretreatment levels of serum bilirubin and bile acids on the prognosis of patients with colorectal cancer (CRC). METHODS: A retrospective cohort of 1474 patients with CRC who underwent surgical resection between January 2015 and December 2017 was included in the study. Survival analysis was used to evaluate the predictive value of pretreatment levels of bilirubin and bile acids. X-Tile software was used to identify optimal cut-off values for total bilirubin (TBIL), direct bilirubin (DBIL) and TBA in terms of overall survival (OS) and disease-free survival (DFS). RESULTS: DBIL, TBIL, and TBA were validated as significant prognostic factors by univariate Cox regression analysis for both 3-year OS and DFS. Multivariate Cox regression analyses confirmed that high DBIL, TBIL and TBA levels were independent prognostic factors for both OS (HR 0.435, 95% CI 0.299-0.637, P < 0.001; HR 0.436, 95% CI 0.329-0.578, P < 0.001; HR 0.206, 95% CI 0.124-0.341, P < 0.001, respectively) and DFS (HR 0.583, 95% CI 0.391-0.871, P = 0.008; HR0.437,95% CI 0.292-0.655, P <0.001; HR 0.634, 95% CI 0.465-0.865, P = 0.004, respectively). In addition, nomograms for OS and DFS were established according to all significant factors, and the c-indexes were 0.819 (95% CI 0.806-0.832) and 0.835 (95% CI 0.822-0.849), respectively. CONCLUSIONS: TBIL, DBIL and TBA levels are independent prognostic factors in colorectal cancer patients. The nomograms based on OS and DFS can be used as a practical model for evaluating the prognosis of CRC patients.