Differentiating benign from malignant idiopathic biliary strictures: are we there yet?

Endoscopic Evaluation of Biliary Strictures: Current and Emerging Techniques

The diagnosis of biliary strictures in clinical practice can be challenging. Discriminating between benign and malignant biliary strictures is important to prevent the morbidity and mortality associated with incorrect diagnoses. Missing a malignant biliary stricture may delay surgery, resulting in poor prognostic outcomes. Conversely, it has been demonstrated that approximately 20% of patients who undergo surgery for suspected biliary malignancies have a benign etiology on histopathology. Traditional tissue sampling using endoscopic retrograde cholangiography does not always produce a definitive diagnosis, with a considerable proportion of cases remaining as indeterminate biliary strictures. Recent advances in endoscopic techniques have the potential to improve the diagnostic and prognostic accuracy of biliary strictures.

Value of bile soluble B7H3 for the diagnosis of malignant biliary strictures: Results of a retrospective study

AIMS

Increasing evidence has demonstrated that serum soluble B7H3(sB7-H3) is a useful tumor marker for cancer diagnosis and prognostic evaluations. Whether sB7-H3 expressed in the bile is related to the progression of malignant biliary strictures must be clarified.

METHODS

Bile sB7-H3 was obtained via endoscopic retrograde cholangiopancreatography (ERCP) from 323 patients suspected to have malignant biliary strictures and was detected using a B7H3 ELISA kit. Diagnostic value was compared among bile sB7-H3, CA19-9, CA12-5, and CEA and ERCP-based cytological/tissue examination. Additionally, the correlations between the bile sB7-H3 concentration and the clinical characteristics of malignant biliary strictures were studied.

RESULTS

The bile sB7-H3 levels of patients with malignant biliary strictures were significantly higher than those in patients with benign biliary strictures (P < 0.001). The AUC values of the receiver operating characteristic(ROC) curves for CA19-9, CA12-5 and CEA were 0.764, 0.475 and 0.399, respectively, which were significantly lower than that of sB7-H3 (0.878); the sensitivities of ERCP-based cytological and tissue examinations were 55.7% and 66.4%, respectively, which were far lower than that of bile sB7-H3(81.2%). A high level of sB7-H3 in patients with malignant biliary strictures was found to be correlated with vascular invasion(P < 0.001), lymph node metastasis(P < 0.001), distant metastasis (P < 0.001) and tumor-node-metastasis (TNM) stage(P = 0.01). The overall survival rate of the patients in the high sB7-H3 group was significantly lower than that of the patients in the low sB7-H3 group(P = 0.014).

CONCLUSIONS

Bile sB7-H3 could serve as a valuable biomarker for patients with malignant biliary strictures and high levels of bile sB7-H3 were associated with poor clinical outcomes.

Novel endoscopic approaches for assessing biliary tract diseases

PURPOSE OF REVIEW

Biliary endoscopy offers both diagnostic and therapeutic value in complex clinical situations. This review addresses the latest advances over the past year in endoscopic approaches of biliary tract diseases.

RECENT FINDINGS

Specifically, we focus on the latest findings on endoscopic retrograde cholangiopancreatography for the evaluation of biliary strictures. In addition, key studies have demonstrated the enhanced role of cholangioscopy, photodynamic therapy in cholangiocarcinoma, and biliary stent technology.

SUMMARY

The following review focuses on the latest advancements in the field of biliary endoscopy. Pivotal studies were selected to highlight some of the current investigations in therapeutic endoscopic retrograde cholangiopancreatography as well as knowledge gaps for future research.

Diagnosis of cholangiocarcinoma

Cholangiocarcinoma is suspected based on signs of biliary obstruction, abnormal liver function tests, elevated tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen), and ultrasonography showing a bile stricture or a mass, especially in intrahepatic cholangiocarcinoma. Magnetic resonance imaging (MRI) or computed tomography (CT) is performed for the diagnosis and staging of cholangiocarcinomas. However, differentiation of an intraductal cholangiocarcinoma from a hypovascular metastasis is limited at imaging. Therefore, reasonable exclusion of an extrahepatic primary tumor should be performed. Differentiating between benign and malignant bile duct stricture is also difficult, except when metastases are observed. The sensitivity of fluorodeoxyglucose positron emission tomography is limited in small, infiltrative, and mucinous cholangiocarcinomas. When the diagnosis of a biliary stenosis remains indeterminate at MRI or CT, endoscopic imaging (endoscopic or intraductal ultrasound, cholangioscopy, or optical coherence tomography) and tissue sampling should be carried out. Tissue sampling has a high specificity for diagnosing malignant biliary strictures, but sensitivity is low. The diagnosis of cholangiocarcinoma is particularly challenging in patients with primary sclerosing cholangitis. These patients should be followed with yearly tumor markers, CT, or MRI. In the case of dominant stricture, histological or cytological confirmation of cholangiocarcinoma should be obtained. More studies are needed to compare the accuracy of the various imaging methods, especially the new intraductal methods, and the imaging features of malignancy should be standardized.