Bilirubin levels predict malignancy in patients with obstructive jaundice.

Background: Differentiating between benign and malignant causes of obstructive jaundice can be challenging, even with the advanced imaging and endoscopic techniques currently available. In patients with obstructive jaundice, the predictive accuracy of bilirubin levels at presentation was examined in order to determine whether such data could be used to differentiate between malignant and benign disease.

Methods: A total of 1,026 patients with obstructive jaundice were identified. Patients were divided into benign and malignant groups. The benign patients were subgrouped into those with choledocholithiasis and those with inflammatory strictures of the biliary tree. Bilirubin levels at presentation and other demographic data were obtained from case records.

Results: Area under the curve (AUC) values for bilirubin as a predictor of malignancy were highly significant for all benign presentations and for those with benign biliary strictures (AUC: 0.8 for both groups; P < 0.001). A bilirubin level > 100 µmol/l was determined to provide the optimum sensitivity and specificity for malignancy in all patients and in those without choledocholithiasis (71.9% and 86.9%, 71.9% and 88.0%, respectively). The application of a bilirubin level > 250 µmol/l achieved specificities of 97.1% and 98.0% in each subgroup of patients, respectively.

Conclusions: In patients with obstructive jaundice, bilirubin levels in isolation represent an important tool for discriminating between benign and malignant underlying causes.