A prospective study of biliary strictures to determine predictors of malignancy

V. G. Bain, N. S. Abraham, M. Hoskinson, G. Jangri, D. C. Sadowski, C. Maguire, T. Alexander, R. Hennig, E. Lalor

Research output: Contribution to journalArticlepeer-review


AIM: To determine the predictive value of biochemistry and imaging in the diagnosis of malignant biliary strictures. METHODS: 31 patients with suspected non-calculous biliary obstruction were consecutively enrolled. A biochemical profile, ultrasound (U/S), HIDA scan and Cholangiography (ERCP or PTC) were obtained at study entry. Stricture etiology was determined based on clinical outcome by one year and/or cytology and histology. Statistical analysis utilized t tests and Mann-Whitney for non-distributive data. RESULTS: 29/31 patients had biliary strictures, 15/29 had malignant strictures. The mean age of the malignant cohort was 73.9 and the benign cohort 53.9 (P=0.0005). Statistically significant differences between the malignant vs benign groups included: ALT 235.2 vs 66.9 IU/L (P=0.002), AST 189.8 vs 84.6 IU/L (P=0.009), ALK PHOS 840.2 vs 361.1 IU/L (P=0.001), BILIRUBIN 317.8 vs 22.1 mmol/L (P<0.001) and BILE ACIDS 242.5 vs 73.2 mmol/L (P=0.001). Threshold analysis using ROC curves demonstrated that a bilirubin level of 75 mmol/L was most predictive of malignant strictures (log odds ratio 16.24). Likelihood ratios were not significantly greater than chance for the other biochemical parameters. Intrahepatic duct dilatation or a pancreatic/intraductal mass on U/S was more prevalent in patients with malignant strictures (14/15 vs 5/14 for dilatation; P=.002 Fisher's exact test). Of 12 patients with malignancy undergoing HIDA scan, 9 showed functional obstruction while 3 showed hepatocellular dysfunction. Among patients with benign strictures, 5 had functional obstruction, 4 had hepatocellular dysfunction and 5 HIDA scans were normal. Cholangiographic characterization of strictures revealed an equal distribution of smooth (8/15) and irregular (5/15) strictures in the malignant group; 10/14 benign strictures were smooth. There was a significant difference in stricture length between malignant vs benign cohorts, 30.30 mm vs 9.20 mm (P=0.0039). Threshold analysis using ROC curves revealed a stricture length of 25 mm was most consistent with malignancy (sensitivity 79%, specificity 75%, log odds ratio 11.23). A multivariate model could not be constructed because in our data set, serum bilirubin perfectly discriminated between benign and malignant strictures. CONCLUSIONS: Serum bilirubin and cholangiographic stricture length are most predictive of malignancy. Ultrasound was useful in predicting malignant strictures in the presence of intrahepatic duct dilatation and pancreatic/intraductal mass. Strictures with a "benign" cholangiographic appearance (smooth or regular) are frequently malignant.

Original languageEnglish (US)
Pages (from-to)AB122
JournalGastrointestinal endoscopy
Issue number4
StatePublished - 1997

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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