Patient selection: biliary strictures, presumably negative for mass lesions along the bile ducts or in the head of the pancreas
Imaging: ERCP (endoscopic retrograde cholangiopancreatography) or PTC (percutaneous cholangiography)
Strictures may be present in the proximal, mid or distal common bile duct. There may be 1 or multiple strictures.
Features of malignant strictures:
(1) older age (mean 62.4 years vs 53 years for benign)
(2) serum total bilirubin > 84 µmol/L (sensitivity 98.6%, specificity 59.3%)
(3) serum alkaline phosphatase > 136 IU/L (sensitivity 60%, specificity 83%)
(4) serum ALT > 68 IU/L (sensitivity 46%, specificity 82%)
(5) serum AST > 85 IU/L (sensitivity 76%, specificity 74%)
(6) proximal biliary dilatation (74% malignant vs 40% benign)
where:
• The normal reference ranges for the laboratory tests are not provided.
About half of the malignant strictures were distal but they can occur anywhere along the length.
While these findings support the diagnosis of malignancy, none are absolutely specific,
