Genetic Abnormalities in Biliary Brush Samples for Distinguishing Cholangiocarcinoma from Benign Strictures in Primary Sclerosing Cholangitis. Gastroenterol Res Pract. 2016;2016:4381513. [PMID: 27127503 PMCID: PMC4834158 DOI: 10.1155/2016/4381513]

The contribution of new methods in cytology for increasing sensitivity in the diagnosis of extrahepatic bile duct lesions

The aim of this review is to provide a comprehensive analysis of the existing literature pertaining to cytology of extrahepatic bile ducts. A search using the keywords "biliary brush cytology" was conducted in the PubMed database, with a focus on recent articles. The inclusion criteria primarily encompassed publications addressing problematic biliary stenosis. Emphasis was placed on identifying articles that explored innovative or less-utilized examination techniques aimed at enhancing the sensitivity of cytological examination. This review presents a comprehensive overview of the various types of materials used in sampling and the corresponding sampling methods. Additionally, it explores cytological and cytogenetic techniques, such as fluorescence in situ hybridization (FISH) and genetic methods (miRNA, NGS, cfDNA). These techniques possess the potential to improve the accuracy of diagnosing bile duct tumors, although their sensitivity varies. Furthermore, their utilization can facilitate early therapy, which plays a crucial role in patient prognosis. Each examination is always dependent on the quality and quantity of material delivered. A higher sensitivity of these examinations can be achieved by combining biliary cytology and other complementary methods.

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.

Impact of trimodality sampling on detection of malignant biliary strictures compared with patients with primary sclerosing cholangitis

BACKGROUND AND AIMS

Malignant biliary strictures can be difficult to diagnose, with up to 20% considered indeterminate after initial tissue sampling. This study aimed to determine the performance characteristics of transpapillary biopsy sampling (TPB) and fluorescence in situ hybridization (FISH) in isolation or in combination with standard brush cytology (BC) in patients who received trimodality sampling for biliary strictures.

METHODS

This single-center retrospective cohort study included patients with biliary strictures undergoing ERCP with trimodality sampling between September 2014 and April 2019. Performance characteristics for each diagnostic test alone and in combination were calculated.

RESULTS

Two hundred four patients underwent trimodality biliary sampling, including 104 (51.0%) with malignancy. The diagnostic sensitivity for malignancy with BC (17.3%) significantly improved with dual modality (BC+FISH, 58.7%; BC+TPB, 40.4%) or trimodality sampling (68.3%; P < .001 for all comparisons). Trimodality sampling improved diagnostic sensitivity for malignancy compared with BC+FISH (P = .002) and BC+TPB (P < .001). There was no statistically significant difference in the sensitivity of trimodality sampling in detecting cholangiocarcinoma (79.7%) compared with pancreatic cancer (62.5%; P = .1). Among 57 patients with primary sclerosing cholangitis (PSC), the sensitivity of detecting biliary malignancy (n = 20) was 20% for BC and significantly improved with the addition of FISH (80%; P < .001) but not with TPB (35.0%; P = .25). Trimodality sampling did not further improve diagnostic sensitivity (85%) over BC+FISH (80%) for malignancy in the setting of PSC (P = 1).

CONCLUSIONS

Trimodality sampling improves the diagnostic sensitivity for the detection of malignant biliary strictures with no significant difference in sensitivity for cholangiocarcinoma compared with pancreatic cancer. However, in patients with PSC, trimodality sampling was not superior to BC+FISH.

Refined pancreatobiliary UroVysion criteria and an approach for further optimization

Pancreatobiliary strictures are a common source of false negatives for malignancy detection. UroVysion is more sensitive than any other method but remains underutilized because of conflicting sensitivities and specificities due to a lack of standardized cutoff criteria and confusion in interpreting results in the context of primary sclerosing cholangitis. We set out to determine the sensitivities and specificities of UroVysion, brushing cytology, forceps biopsies, and fine needle aspiration (FNAs) for pancreatobiliary stricture malignancy detection. A retrospective review was performed of all biopsied pancreatobiliary strictures at our institution over 5 years. UroVysion was unquestionably the most sensitive method and all methods were highly specific. Sensitivity was highest while maintaining specificity when a malignant interpretation was limited to cases with 5+ cells with the same polysomic signal pattern and/or loss of one or both 9p21 signals. Only UroVysion detected the metastases and a neuroendocrine tumor. In reviewing and analyzing the signal patterns, we noticed trends according to location and diagnosis. Herein we describe our method for analyzing signal patterns and propose cutoff criteria based upon observations gleaned from such analysis.

Cholangiocarcinoma in Patients with Primary Sclerosing Cholangitis (PSC): a Comprehensive Review

Cholangiocarcinoma (CCA) is the most common malignancy in patients with primary sclerosing cholangitis (PSC) and carries a high rate of mortality. Although the pathogenesis of CCA in PSC is largely unknown, inflammation-driven carcinogenesis concomitant with various genetic and epigenetic abnormalities are underlying factors. The majority of CCA cases develop from a dominant stricture (DS), which is defined as a stricture with a diameter < 1.5 mm in the common bile duct or < 1.0 mm in the hepatic duct. In PSC patients presenting with an abrupt aggravation of jaundice, pain, fatigue, pruritus, weight loss, or worsening liver biochemistries, CCA should be suspected and evaluated utilizing a variety of diagnostic modalities. However, early recognition of CCA in PSC remains a major challenge. Importantly, 30-50% of CCA in PSC patients are observed within the first year following the diagnosis of PSC followed by an annual incidence ranging from 0.5 to 1.5 per 100 persons, which is nearly 10 to 1000 times higher than that in the general population. Cumulative 5-year, 10-year, and lifetime incidences are 7%, 8-11%, and 9-20%, respectively. When PSC-associated CCA is diagnosed, most tumors are unresectable, and no effective medications are available. Given the poor therapeutic outcome, the surveillance and management of PSC patients who are at an increased risk of developing CCA are of importance. Such patients include older males with large-duct PSC and possibly concurrent ulcerative colitis. Thus, more attention should be paid to patients with these clinical features, in particular within the first year after PSC diagnosis. In contrast, CCA is less frequently observed in pediatric or female PSC patients or in those with small-duct PSC or concurrent Crohn's disease. Recently, new biomarkers such as antibodies to glycoprotein 2 have been found to be associated with an increased risk of developing CCA in PSC. Herein, we review the literature on the pathogenesis, incidence, clinical features, and risk factors, with a focus on various diagnostic modalities of PSC-associated CCA.

Detecting cholangiocarcinoma in patients with primary sclerosing cholangitis - The promise of DNA methylation and molecular biomarkers

Cholangiocarcinoma (CCA) is a highly fatal malignancy of the bile ducts that arises in up to 20% of patients with primary sclerosing cholangitis (PSC). Current detection methods for CCA display suboptimal sensitivity and/or specificity, and there is no evidence-based screening strategy for CCA in patients with PSC. Consequently, CCA is often detected too late for surgical resection, contributing to the high mortality associated with this malignancy. Recently, biomarkers have emerged with potential to complement current detection methods, and/or be used for cancer surveillance in high-risk patient groups, including patients with PSC. Aberrant DNA methylation patterns represent promising biomarkers with great potential for CCA detection. Such aberrations are frequent in CCA, often occur early, and can be detected in liquid biopsies, including blood, bile and urine. This review summarises and highlights the most promising DNA methylation biomarkers identified for CCA detection so far, focusing on patients with PSC. Other promising molecular biomarkers for detection of PSC-associated CCA in liquid biopsies will also be briefly covered.

Role of fluorescence in situ hybridization in diagnosing cholangiocarcinoma in indeterminate biliary strictures

BACKGROUND AND AIM

Brush cytology, the conventional method to diagnose cholangiocarcinoma, has been plagued by low diagnostic sensitivity and false-negative results. This paper aims to study the clinical utility of fluorescence in situ hybridization (FISH) in enhancing identification of malignant biliary strictures.

METHODS

Brush cytologic specimens collected from endoscopic retrograde cholangiopancreatography for biliary strictures in a tertiary hospital in Singapore from March 2013 to July 2015 were examined by FISH technique using UroVysion probe set in this study.

RESULTS

Thirty patients were chosen with five patients having multiple FISH performed due to indeterminate results. The diagnoses for biliary strictures were 13 (43.3%) cholangiocarcinomas, seven (23.3%) pancreatic cancers, seven (23.3%) benign biliary strictures, and three (10%) primary sclerosing cholangitis. Conventional brush cytology had sensitivity of 53.8% with specificity of 82.4%. FISH had sensitivity of 30.8% with specificity of 100%. When FISH results were interpreted in cases with negative or atypical brush cytology, two patients had positive FISH results and cholangiocarcinomas. Based on this pilot study, FISH increased sensitivity of brush cytology in detection of cholangiocarcinoma from 53.8% to 69.2% while preserving specificity of 82.4%.

CONCLUSION

Compared with conventional cytology with low sensitivity, FISH may help to increase sensitivity on top of brush cytology while maintaining high specificity.

Suspicious brush cytology is an indication for liver transplantation evaluation in primary sclerosing cholangitis

AIM

To investigate markers for high-grade dysplasia for the optimal timing of liver transplantation in patients with primary sclerosing cholangitis (PSC).

METHODS

Earlier data support a dysplasia-carcinoma sequence, even low- to high-grade dysplasia, in PSC-associated cholangiocarcinoma (CCA). Surveillance using endoscopic retrograde cholangiography (ERC) and brush cytology aims to detect cases of biliary dysplasia, and liver transplantation is an option in cases with suspicion of malignancy in brushing. This study investigated markers to identify patients with high-grade biliary dysplasia for optimal timing in early liver transplantation. Patients undergoing surveillance using ERC and brush cytology during 2008-2014 and who were diagnosed with biliary dysplasia in explanted liver or CCA until February 2016 were included in the study. Demographic data, cholangiography findings, laboratory values, cytological morphology and DNA ploidy were analysed.

RESULTS

Thirty PSC patients had biliary neoplasia in the explanted liver during the study period. Sixteen of these patients had low-grade dysplasia, 10 patients had high-grade dysplasia, and 4 patients had CCA. Fifteen PSC patients diagnosed with CCA were not transplanted. Patients with low-grade dysplasia were younger. Alkaline phosphatase or carcinoembryonic antigen values did not differ between groups during surveillance, but carbohydrate antigen 19-9 was higher in CCA patients. No difference in PSC duration, ERC scores, suspicious cytology, or ploidy analysis was found between groups. No difference was observed between fibrosis stage in explanted livers. Low- and high-grade dysplasia could not be differentiated before liver transplantation based on liver enzymes, tumour markers, ERC scores, brush cytology or DNA ploidy.

CONCLUSION

Repeated suspicion of neoplasia in brush cytology should be an indication for evaluations of liver transplantation prior to the development of CCA.

Risk of cholangiocarcinoma in patients with primary sclerosing cholangitis: diagnosis and surveillance

PURPOSE OF REVIEW

Primary sclerosing cholangitis (PSC) is associated with an increased risk of hepatobiliary and extrahepatic malignancy. Particularly the risk of cholangiocarcinoma (CCA) is greatly increased. To provide potentially curative treatments for affected patients an early diagnosis of CCA is crucial. We here review the current advances with respect to CCA diagnosis and surveillance and discuss a rational approach on how to perform surveillance of CCA in PSC patients.

RECENT FINDINGS

Given the shortcomings of the current modalities for the surveillance and diagnosis of CCA in PSC, recent studies have focused on novel biomarkers for CCA. These include serum biomarkers (e.g., circulating angiopoeitin-2, cytokeratin-19 fragments, and antiglycoprotein 2 IgA autoantibodies, microRNA) as well as proteomics obtained from urine and/or bile. Novel approaches that may enhance the diagnostic value of brush cytology in future include the optimization of fluorescence in situ hybridization probes and the assessment of genetic aberrations. In addition, studies on advanced techniques (e.g., single-operator cholangioscopy and probe-based confocal laser endomicroscopy) have shown promising results with respect to CCA detection.

SUMMARY

Despite recent advances in the diagnosis of CCA in PSC, the detection of early-stage CCA remains difficult. A better understanding of CCA pathogenesis and large prospective studies on novel biomarkers and techniques are required to timely diagnose CCA in the future.