The prognostic value of serum bilirubin in colorectal cancer patients with surgical resection.

Purpose: Serum bilirubin plays an important role in antioxidant and anticancer processes. The inverse association between serum bilirubin and cancer risk have been widely reported in multiple cancers. The aim of this retrospective study was to investigate the prognostic impact of serum bilirubin in colorectal cancer patients undergoing surgical resection.

Methods: The value of serum bilirubin including total bilirubin, direct bilirubin, and indirect bilirubin were tested at pre-operatively in 330 colorectal cancer patients. The optimal cut-off values for these three biomarkers were determined by X-tile program. The relationship between serum bilirubin and outcomes were examined using Kaplan-Meier curves log-rank test, univariate and multivariate cox regression. Moreover, a number of risk factors were used to form a nomogram for evaluating risk of survival.

Results: The optimal cut-off points of serum total bilirubin, direct bilirubin, and indirect bilirubin were 19.5 μmol/L, 5.0 μmol/L and 8.1 μmol/L, respectively. Elevated total bilirubin and direct bilirubin were significantly associated with overall survival in surgical colorectal cancer patients. Additionally, predictive nomogram including total bilirubin and direct bilirubin for overall survival was established for predicting overall survival in surgical colorectal cancer patients.

Conclusions: These findings indicated that preoperative elevated total bilirubin and direct bilirubin could be considered as independent prognostic biomarkers for poor overall survival of colorectal cancer patients.