Researchers identified abdominal pain, low serum carbohydrate antigen (CA) 19.9 levels, and absence of mass on imaging as independent predictors of benign lesions in patients with proximal biliary strictures (PBS), as indicated by study data published in HPB. According to the researchers, the aforementioned risk factors may be used to differentiate benign lesions from perihilar cholangiocarcinoma (PHC) in patients with PBS.

The prospective study enrolled patients with PBS who were referred to a specialist Hepato-Pancreatico-Biliary clinic in Birmingham, UK, between 2008 and 2016. Clinical, laboratory, and radiological data were abstracted from electronic medical records. Patients with primary sclerosing cholangitis, metastatic PHS, or hilar obstruction by a peripheral tumor were excluded. Cross-sectional and cholangiography images from each patient were reviewed by a specialist hepatobiliary radiologist who was blinded to the final diagnosis. The following radiological features were assessed by the specialist: stricture count and length; presence of mass; duct and/or lesion enhancement; and ductal separation. Final diagnosis of benign or malignant lesion was determined by biopsy and/or resection histology. In patients, who did not undergo resection, a combination of imaging and clinical course was used to ascertain diagnosis. Multivariable regression was performed to identify potential predictors of benign or malignant diagnoses.

A total of 155 consecutive patients were included in analyses, of whom 55 (36%) were men. Median age at referral was 68 years (interquartile range [IQR], 61-73). Overall, 112 patients (72%) presented without abdominal pain and 123 (79%) were clinically jaundiced. Mean serum bilirubin and CA19.9 levels upon referral were 150 μmol/L (IQR, 41–272) and 253 U/mL (IQR, 65–970), respectively. A total of 55 patients (35%) were considered to have either suspected (n=27) or biopsy-confirmed (n=28) resectable PHC and underwent surgery. Of the 100 patients who did not undergo surgery, 68 had biopsy-confirmed PHC but were either unfit for surgery or had inoperable disease as indicated by imaging. The remaining 32 patients underwent clinical and radiological follow-up, during which 14 (44%) were diagnosed with cholangiocarcinoma and 18 (56%) with benign disease. In the cohort, 25 patients (16%) ultimately received a diagnosis of benign disease. Predictors of benign proximal biliary strictures included abdominal pain (OR, 3.36; P =.027), serum CA19.9 <100 U/mL (OR, 10.35; P =.001), and absence of mass on imaging (OR, 4.66; P =.004). Median (IQR) serum bilirubin levels were significantly elevated in patients with malignant vs benign strictures (168 [47-283] vs 42 [14-182] μmol/L; P =.012). However, this association was not significant in multivariable analyses. 

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According to the researchers, the results from this analysis may allow for stratification of risk among candidates for surgery. Surgical management of PHC is associated with significant morbidity and mortality, and presurgical biopsy sensitivity is only 69-75%. Presurgery assessment of malignancy risk may be important in reducing unnecessary surgical risks. Given the small cohort size, however, results must be extrapolated with care. Statistical power was limited due to the small number of patients with benign vs malignant pathologies. Further study is necessary to confirm these potential predictors of benign disease. “There is…an urgent need to stratify patients according to the risk of malignancy, and our analysis has identified an association between serum bilirubin, CA19.9, and the presence of a mass on CT scan with a malignant stricture,” researchers wrote.

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Reference

Tirotta F1, Giovinazzo F1, Hodson J, et al. Risk factors to differentiate between benign proximal biliary strictures and perihilar cholangiocarcinoma [published online April 19, 2020]. HPB (Oxford). doi: 10.1016/j.hpb.2020.03.023