Optimal tissue sampling during ERCP and emerging molecular techniques for the differentiation of benign and malignant biliary strictures

Morphologic and molecular diagnostic criteria of malignancies in biliary strictures

The differential diagnosis of benign and malignant biliary strictures is not always feasible and still represents a major diagnostic challenge, mainly due to the scarcity of the tissue retrieved for proper cytological or histopathological diagnosis. The present review focuses on morphological criteria in the diagnosis of biliary strictures, in the course of primary sclerosing cholangitis and other pathologies, starting from the limits of the cytological and histological evaluation, as well as the ancillary methodologies currently available in Pathology laboratories The current guidelines suggest fluorescence in situ hybridization for the analysis of chromosomes 3, 7, and 17 polysomies and deletion of the 9p21 locus; however, other more promising techniques are on the horizon for both patient care and research purposes, such as Next-Generation Sequencing, able to analyze multiple genes simultaneously in a cost-effective fashion. Lastly, the most recent approaches proposed in the literature for the differential diagnosis of biliary stricture are described, such as circulating tumor DNA, miRNAs, and DNA methylation, among others.

Combining brushing cytology with simultaneous vacuum aspiration in suspicious biliopancreatic malignancies: A multicenter propensity score-matched study (with video)

BACKGROUND

Brush cytology during endoscopic retrograde cholangiopancreatography (ERCP) is a standard approach in diagnosing biliopancreatic strictures, with yet unsatisfying sensitivity.

AIMS

We brought additional simultaneous vacuum aspiration to brushing process and re-evaluate the diagnostic performance.

METHODS

This multi-centered retrospective study was conducted in three tertiary centers. Consecutive patients with biliopancreatic strictures were identified. The patients were divided into two arms: the conventional arm (CA) receiving general brushing approach, and the modified arm (MA) being treated with additional vacuum aspiration when performing bushing. The 1:1 propensity-score matching was implemented to tackle the selective biases.

RESULTS

A total of 555 patients were identified and 200 patient pairs (193 males, 207 females, with a mean age of 68.1 ± 13.1 years.) fell into the ultimate evaluation. A final diagnosis of malignant stricture was established in 243 patients. The diagnostic yield of the MA group was substantially better than that of the CA group, whether "suspicious malignancies" were considered malignancies or not. The rates of sensitivity, specificity and accuracy were 46.2%, 100%, 68.0% in the MA group, and 15.3%, 98.7%, and 47.0% in the CA group respectively.

CONCLUSIONS

Brushing accompanied by simultaneous vacuum aspiration at ERCP improves the diagnostic yield in suspicious biliopancreatic malignancies.

Cholangiocarcinoma: Pathologic and Molecular Classification in the Era of Precision Medicine

CONTEXT.—

Cholangiocarcinoma (CCA) is a heterogeneous cancer of the bile duct, and its diagnosis is often challenging.

OBJECTIVE.—

To provide insights into state-of-the-art approaches for the diagnosis of CCA.

DATA SOURCES.—

Literature review via PubMed search and authors' experiences.

CONCLUSIONS.—

CCA can be categorized as intrahepatic or extrahepatic. Intrahepatic CCA is further classified into small-duct-type and large-duct-type, whereas extrahepatic CCA is classified into distal and perihilar according to site of origin within the extrahepatic biliary tree. Tumor growth patterns include mass forming, periductal infiltrating, and intraductal tumors. The clinical diagnosis of CCA is challenging and usually occurs at an advanced tumor stage. Pathologic diagnosis is made difficult by tumor inaccessibility and challenges in distinguishing CCA from metastatic adenocarcinoma to the liver. Immunohistochemical stains can assist in differentiating CCA from other malignancies, such as hepatocellular carcinoma, but no distinctive CCA-specific immunohistochemical profile has been identified. Recent advances in next-generation sequencing-based high-throughput assays have identified distinct genomic profiles of CCA subtypes, including genomic alterations that are susceptible to targeted therapies or immune checkpoint inhibitors. Detailed histopathologic and molecular evaluations of CCA by pathologists are critical for correct diagnosis, subclassification, therapeutic decision-making, and prognostication. The first step toward achieving these goals is to acquire a detailed understanding of the histologic and genetic subtypes of this heterogeneous tumor group. Here, we review state-of-the-art approaches that should be applied to establish a diagnosis of CCA, including clinical presentation, histopathology, staging, and the practical use of genetic testing methodologies.

Using Endoscopy in the Diagnosis of Pancreato-Biliary Cancers

Pancreatic cancer and cholangiocarcinoma are life threatening oncological conditions with poor prognosis and outcome. Pancreatic cystic lesions are considered precursors of pancreatic cancer as some of them have the potential to progress to malignancy. Therefore, accurate identification and classification of these lesions is important to prevent the development of invasive cancer. In the biliary tract, the accurate characterization of biliary strictures is essential for providing appropriate management and avoiding unnecessary surgery. Techniques have been developed to improve the diagnosis, risk stratification, and management of pancreato-biliary lesions. Endoscopic ultrasound (EUS) and associated techniques, such as elastography, contrasted-enhanced EUS, and EUS-guided needle confocal laser endomicroscopy, may improve diagnostic accuracy. In addition, intraductal techniques applied during endoscopic retrograde cholangiopancreatography (ERCP), such as new generation cholangioscopy and in vivo cellular evaluation through probe-based confocal laser endomicroscopy, can increase the diagnostic yield in characterizing indeterminate biliary strictures. Both EUS-guided and intraductal approaches can provide the possibility for tissue sampling with new tools, such as needles, biopsies forceps, and brushes. At the molecular level, novel biomarkers have been explored that provide new insights into diagnosis, risk stratification, and management of these lesions.

Fluorescence In Situ Hybridization in Primary Diagnosis of Biliary Strictures: A Single-Center Prospective Interventional Study

Background and aims: Diagnosis of the biliary stricture remains a challenge. In view of the low sensitivity of brush cytology (BC), fluorescence in situ hybridization (FISH) has been reported as a useful adjunctive test in patients with biliary strictures. We aimed to determine performance characteristics of BC and FISH individually and in combination (BC + FISH) in the primary diagnosis of biliary strictures. Methods: This single-center prospective study was conducted between April 2019 and January 2021. Consecutive patients with unsampled biliary strictures undergoing first endoscopic retrograde cholangiopancreatography in our institution were included. Tissue specimens from two standardized transpapillary brushings from the strictures were examined by routine cytology and FISH. Histopathological confirmation after surgery or 12-month follow-up was regarded as the reference standard for final diagnosis. Results: Of 109 enrolled patients, six were excluded and one lost from the final analysis. In the remaining 102 patients (60.8% males, mean age 67.4, range 25–92 years), the proportions of benign and malignant strictures were 28 (27.5%) and 74 (72.5%), respectively. The proportions of proximal and distal strictures were 26 (25.5%) and 76 (74.5%), respectively. In comparison to BC alone, FISH increased the sensitivity from 36.1% to 50.7% (p = 0.076) while maintaining similar specificity (p = 0.311). Conclusions: Dual-modality tissue evaluation using BC + FISH showed an improving trend in sensitivity for the primary diagnosis of biliary strictures when compared with BC alone.

Next-generation sequencing mutation analysis on biliary brush cytology for differentiation of benign and malignant strictures in primary sclerosing cholangitis

BACKGROUND AND AIMS

Differentiation of benign and malignant biliary tract strictures on brush material remains highly challenging but is essential for adequate clinical management of patients with primary sclerosing cholangitis (PSC). In this case-control study, biliary brush cytology samples from PSC patients with cholangiocarcinoma (PSC-CCA) were compared with samples from PSC patients without CCA (PSC-control subjects) using next-generation sequencing (NGS).

METHODS

Cells on archived slides were dissected for DNA extraction. NGS was performed using a gene panel containing 242 hotspots in 14 genes. Repeated brush samples from the same patient were analyzed to study the consistency of NGS results. In PSC-CCA cases that underwent surgical resection, molecular aberrations in brush samples were compared with NGS data from subsequent resection specimens.

RESULTS

Forty patients (20 PSC-CCA and 20 PSC-control subjects) were included. The gene panel detected 22 mutations in 15 of 20 PSC-CCA brush samples, including mutations in TP53 (8 brush samples), K-ras (5), G-nas (3), ERBB2 (1), APC (1), PIK3CA (1), and SMAD4 (1). One G-nas and 3 K-ras mutations were found in 3 of 20 PSC-control brush samples. The sensitivity of the NGS panel was 75% (95% confidence interval, 62%-80%) and specificity 85% (95% confidence interval, 64%-95%). Repeated brush samples showed identical mutations in 6 of 9 cases. Three repeated brush samples demonstrated additional mutations as compared with the first brush sample. In 6 of 7 patients, mutations in brush samples were identical to mutations in subsequent resection specimens.

CONCLUSIONS

NGS mutation analysis of PSC brush cytology detects oncogenic mutations with high sensitivity and specificity and seems to constitute a valuable adjunct to cytologic assessment of brush samples.

Advanced endoscopy meets molecular diagnosis of cholangiocarcinoma

Cholangiocarcinoma remains an aggressive and deadly malignancy that is often diagnosed late. Intrinsic tumour characteristics and the growth pattern of cancer cells contribute to the challenges of diagnosis and chemoresistance. However, establishing an early and accurate diagnosis, and in some instances identifying targetable changes, has the potential to impact survival. Primary sclerosing cholangitis, a chronic cholangiopathy prodromal to the development of a minority of cholangiocarcinomas, poses a particular diagnostic challenge. We present our diagnostic and theranostic approach to the initial evaluation of cholangiocarcinomas, focusing on extrahepatic cholangiocarcinoma. This involves a multipronged strategy incorporating advanced imaging, endoscopic methods, multiple approaches to tissue sampling, and molecular markers. We also provide an algorithm for the sequential use of these tools.

Pathological and molecular diagnoses of early cancer with bile and pancreatic juice

The dismal prognosis of pancreaticobiliary malignancies is mainly attributed to the extremely difficult detection of early-stage lesions, including intraepithelial neoplasia. To improve prognosis, several studies on the early detection of cancer have been conducted using bile and pancreatic juices for pathological or molecular analyses. One approach is liquid biopsy that includes information about the tumor, such as circulating tumor cells, circulating tumor DNA, microRNAs, and exosomes released by the tumor. Another approach is proteomics/metabolomics that reflects specific conditions in the tumor. These two approaches lead to artificial intelligence-based multiomics analyses that comprises genomics, proteomics/metabolomics, and transcriptomics. Based on the findings of molecular analysis, pathological analysis using immunohistochemical staining/fluorescence in situ hybridization has also been developed. Moreover, there have been reports of new methods/ingenuities for obtaining appropriate samples for the diagnosis of early-stage cancer. Here we review the knowledge on cutting-edge pathological and molecular analyses of bile and pancreatic juices, introduce some ingenuities in sampling and sample processing to promote effective clinical practice, and provide a basis for future studies.

Histological assessment of new cholangioscopy-guided forceps in ERCP biliary stricture sampling: a blinded comparative study

Background and study aims  Obtaining quality tissue during ERCP biliary stricture sampling is of paramount importance for a timely diagnosis. While single-operator cholangioscopy (SOC)-guided biopsies have been suggested to be the superior biliary tissue acquisition modality given direct tissue visualization, less is known about the specimen histological quality. We aimed to analyze the specimen quality of SOC biopsies and compare the new generation forceps with prior "legacy" forceps. Patients and methods  Patients who underwent SOC from January 2017-August 2021 for biliary sampling were reviewed. In February 2020, the SOC-guided biopsy forceps were changed from legacy SpyBite to the SpyBite Max forceps (max). Specimens were assessed by blinded pathologists for crush artifact (none, mild, or severe) and gross size (greatest dimension in mm). Crush artifact and gross size were compared between the two groups. The diagnostic performance characteristics for cholangiocarcinoma (CCA), were assessed in an exploratory fashion. Results  Eighty-one patients (max = 27, legacy = 54) with similar baseline characteristics were included in this study. On blinded pathological assessment, 58 % had crush artifact, without significant differences between the two groups (Max 63 % vs. Legacy 56 %; P  = 0.64). A similar mean specimen size was found (max 3 mm vs. legacy 3.2 mm; P  = 0.24). The overall prevalence of CCA was 40 %. The sensitivity, specificity, positive predictive value, and negative predictive value of the entire cohort using a combination of cytology, fluorescence in situ hybridization, and SOC-guided biopsies were 78.1 %, 91.8 %, 86.2 %, and 86.5 %, respectively. No difference between legacy or max groups was found. Conclusions  A high rate of crush artifact was found in SOC-guided biopsy specimens. Further investigation regarding proper biopsy technique and handling is necessary to increase the diagnostic yield with SOC-guided biopsies.

Optimal Management of Patients with Advanced or Metastatic Cholangiocarcinoma: An Evidence-Based Review

Cholangiocarcinomas are rare tumors originating at any point along the biliary tree. These tumors often pose significant challenges for diagnosis and treatment, and often carry a poor prognosis. However, in recent years, studies have identified significant molecular heterogeneity with up to 50% of tumors having detectable mutations, leading to the guideline recommendations for molecular testing as part of the diagnostic workup for these tumors. In addition, better classification of these tumors and understanding of their biology has led to new drugs being approved for treatment of this resistant tumor. This manuscript will provide a comprehensive review of the epidemiology, risk factors, diagnostic approach, molecular classification, and treatment options for patients with advanced cholangiocarcinomas.