Sensitivity of alternative testing for pancreaticobiliary cancer: a 10-y review of the literature

Diagnostic utility of quantitative analysis of microRNA in bile samples obtained during endoscopic retrograde cholangiopancreatography for malignant biliary strictures

BACKGROUND

The sensitivity of bile cytology for malignant biliary strictures is not adequate. To overcome this limitation, we evaluated whether quantitative analysis of microRNAs (miRNAs) in bile can provide a precise diagnosis of malignant biliary strictures due to pancreatic cancer (PC) and biliary tract cancer (BTC).

METHODS

This was a retrospective evaluation of miRNA levels in stored bile samples of patients with PC, BTC or benign biliary stricture obtained during biliary drainage from April 2019 to December 2021 at our institution. A total of 113 patients (PC; n = 40, BTC; n = 38, control; n = 35) were enrolled. The miRNA candidates to be quantified were determined with microarray analysis from each 3 patients with PC, BTC and controls.

RESULTS

Using microarray analysis, we confirmed four significantly up-regulated miRNAs (miR-1275, miR-6891-5p, miR-7107-5p, miR-3197) in patients with PC and BTC compared to control patients. Quantitative PCR was then performed in 113 bile samples for these miRNAs. miR-1275 was significantly upregulated in PC (p = 0.003) and BTC (p = 0.049) compared to controls, miR-6891-5p was significantly upregulated in PC compared to controls (p = 0.025). In particular, a combination of bile cytology and miR-1275 in bile showed a sensitivity of 77.5% (95% CI, 70.7-77.5%), specificity of 100% (95% CI, 92.2-100%) and an area under the curve (AUC) of 0.93, and provided a significantly greater additional diagnostic effect than bile cytology alone (p = 0.014).

CONCLUSIONS

This study suggest that bile miRNAs could be potential biomarkers for pancreato-biliary diseases, particularly miR-1275 and miR-6891-5p may be helpful in the diagnosis of PC and BTC.

Antibody array-based proteomic screening of novel biomarkers in malignant biliary stricture

BACKGROUND

Distinguishing between benign and malignant bile duct strictures has long been a diagnostic challenge in clinical practice.

OBJECTIVE

This study aimed to discover novel biomarkers in bile to improve the diagnostic accuracy of malignant biliary strictures.

METHODS

Bile samples were collected from 6 patients with malignant or benign biliary stricture, respectively. Protein profiles of the bile were analyzed with a semi-quantitative human antibody array of 440 proteins. Then the differential expressed proteins were screened by Venn diagram analysis. Following this, the accuracy of these potential biomarkers for discriminating between malignant and non-malignant biliary strictures was validated in a larger (n= 40) group of patients using lasso analysis.

RESULTS

Twenty proteins were found differentially expressed in malignant versus benign biliary strictures, 6 of which were identified by Venn diagram analysis to be up-regulated regardless of the location of biliary strictures. Among the 6 biomarkers, bile lipocalin-2, P-cadherin, and adipsin showed better diagnostic utility than that of bile CA19-9. Lasso analysis identified that lipocalin-2, P-cadherin and CA19-9 as a group of makers best distinguished malignant from benign strictures.

CONCLUSIONS

Lipocalin-2 and P-cadherin measurements in bile could be clinically useful for the detection of malignant biliary strictures.

Cytomorphologic characteristics of next-generation sequencing-positive bile duct brushing specimens

INTRODUCTION

Cytology of bile duct brushings (BDBs) is a specific, but insensitive, test for malignancy. Next-generation sequencing (NGS) of BDBs has recently been shown to improve sensitivity. We analyzed the cytologic features of NGS-positive (NGS⁺) and NGS-negative (NGS^-) BDBs and correlated the morphology with the presence of mutations.

MATERIALS AND METHODS

A total of 96 BDBs were analyzed for 29 cytologic features by 2 pathologists who were unaware of the original diagnosis and NGS results. Clinicopathologic follow-up was used to determine the patient outcomes (ie, benign, low-grade neoplasm, malignant [carcinoma/high-grade dysplasia]).

RESULTS

We analyzed 74 NGS⁺ BDBs from 66 patients and 22 NGS^- BDBs from 22 patients. During follow-up, 58 of 66 NGS⁺ patients (88%) had malignancy compared with 0% of NGS^- patients (P < 0.001). Fewer than 50% of the malignant cases had been interpreted as malignant on cytology; however, 100% had demonstrated mutations using NGS. Within the NGS⁺ cases, 53% showed late mutations (TP53, SMAD4, and CDKN2A) supportive of a high-risk stricture. Significant morphologic differences were seen in the background appearance, presence of single cells, architectural disarray, nucleomegaly, anisonucleosis, irregular nuclear borders, increased nuclear/cytoplasmic ratio, nuclear hyperchromasia, nucleoli, abnormal groups, clusters, and/or single cells, and overall impression. Naked nuclei, nucleomegaly, anisonucleosis, and coarse chromatin were more common in BDBs with late mutations than in those with KRAS/GNAS (Kirsten rat sarcoma viral oncogene homolog/guanine nucleotide binding protein, α-stimulating complex locus) mutations only. Cytology had a sensitivity of 16% and a specificity of 100% for malignancy. In contrast, NGS had a sensitivity of 100% and a specificity of 73%. Late mutations were 100% specific for malignancy compared with mutations in KRAS/GNAS only, of which 69% were malignant.

CONCLUSIONS

We found significant overlap in the cytomorphologic features between neoplastic and non-neoplastic BDBs, and more than one half of cancer cases had been interpreted as "nonmalignant" on cytology. NGS showing late mutations was 100% specific for malignancy. Adding genetic testing to BDB cytology would be a valuable ancillary test for the detection of malignancy, and reflex testing should be considered.

Insulin-like growth factor 2 binding protein 3 expression on endoscopic ultrasound guided fine needle aspiration specimens in pancreatic ductal adenocarcinoma

BACKGROUND

Despite numerous investigations, we still do not have a specific marker for pancreatic ductal adenocarcinoma. Only guideline-recommended biomarker for pancreatic ductal adenocarcinoma is the CA19-9, but it is also present in other gastrointestinal diseases. IMP3 is a new potential biomarker that is over-expressed in some cancers. The aims of our study were (1) to assess IMP3 in benign pancreatic lesions and pancreatic cancer, and (2) to estimate its concentrations in localized and advanced pancreatic cancer.

PATIENTS AND METHODS

Seventy-five patients with solid pancreatic lesions who underwent EUS-FNA were included. Patients were divided into three groups: benign lesions, cancer localized only on the pancreas, and patients with advanced pancreatic cancer (locally advanced or with distal metastases). Immunoreactivity of IMP3 was assessed on cytological smears sampled by endoscopic ultrasound.

RESULTS

IMP3 was expressed in 89% of the patients with pancreatic cancer and not in benign lesions. Stronger expression of IMP3 protein and stage of the pancreatic cancer was statistically significant. IMP3 was expressed in all localized cancers and in 85% of patients with advanced pancreatic cancer. In the subgroup with locally advanced cancer, IMP3 was expressed in 88%, and in 83% of patients in the subgroup with distal metastasis (P = 0.007). In the present study, sensitivity was 89%, specificity 100%, with positive predictive value of 100% and negative predictive value of 63%.

CONCLUSION

There is a positive correlation between IMP3 expression and TNM stages of the pancreatic cancer. Higher expression of IMP3 on EUS-FNA specimens can suggest poorer prognosis.

Protein Signatures and Tissue Diagnosis of Pancreatic Cancer

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration fails to diagnose up to 25% of patients with pancreatic ductal adenocarcinoma (PDAC). Proteomics can help to overcome this clinical dilemma. We hypothesized that soluble protein signatures can differentiate PDAC from benign tissues.

STUDY DESIGN

Tissues were obtained from resected surgical specimens, lysed, and homogenates collected for analysis with a 41-protein multiplex assay. Analyte concentrations were normalized to total protein. Statistical analysis was performed to evaluate for differences in PDAC vs benign tissue.

RESULTS

Tissues were obtained from 159 patients, 82 patients with PDAC naïve to therapy and 77 with benign pancreatic pathology. Fourteen analytes had a receiver operating characteristic curve area of >0.75 for predicting PDAC vs benign tissue. A recursive partitioning model using only 2 analytes, interleukin 1 receptor antagonist and transforming growth factor-α, provided an accuracy, sensitivity, and specificity of 91.2%, 90.2%, and 92.2%, respectively. A penalized logistic regression model found 12 analytes that provide diagnostic value to a protein signature. The mean area under the receiver operating characteristic after 50 tenfold cross-validations was 0.951. Accuracy, sensitivity, and specificity of this model were 91.2%, 87.8%, and 94.8%, respectively. Applying the scenario of 80% disease prevalence in patients undergoing endoscopic ultrasound with fine-needle aspiration for a pancreatic head mass, positive predictive value is 98.5% (95% CI 93.0% to 99.7%) and negative predictive value is 66.0% (95% CI 54.9% to 75.6%).

CONCLUSIONS

Protein signatures from pancreatic specimens can differentiate PDAC from benign tissue. Additional work to validate these findings in a unique sample set is warranted.

Design of an immunohistochemistry biomarker panel for diagnosis of pancreatic adenocarcinoma

BACKGROUND

Challenges still exist in differentiating pancreatic adenocarcinoma from benign disease. The use of adjuvant testing of tissue biopsies has demonstrated potential diagnostic value. We designed a proof of concept study to first validate four individual immunohistochemistry biomarkers and then combine them into a panel to boost overall diagnostic sensitivity.

METHODS

Malignant and benign pancreas from 27 pancreaticoduodenectomy specimens underwent immunohistochemistry staining with VHL, IMP3, S100A4, S100P. Using ROC curve analysis, threshold criteria for number of cells staining were chosen for each biomarker. Biomarkers were then evaluated as a panel for their ability to discriminate malignant from benign specimens.

RESULTS

Diagnostic sensitivity of VHL, IMP3, S100A4, and S100P were 75.0%, 79.2%, 45.8%, and 0%. When VHL, IMP3, and S100A4 were grouped into a panel, they were able to distinguish cancer from normal tissue with a sensitivity of 100% and a specificity of 96%.

CONCLUSIONS

The high diagnostic value of an IHC panel consisting of VHL, IMP3, and S100A4 on surgical specimens suggests the need for future prospective studies of these biomarkers on biopsy specimens.

Yield of biliary stent cytology: Is it time to think lean?

Background and study aims  During evaluation of pancreaticobiliary strictures, it is common practice to send biliary stents for cytologic analysis. However, in recent years, complementary tissue acquisition techniques ranging from cholangioscopy to fine-needle biopsy have improved the ability to acquire tissue and diagnose malignancy. Data are limited on the current diagnostic yield and cost effectiveness of biliary stent analysis. Patients and methods  We performed a retrospective study of all pancreaticobiliary stents sent for analysis in a tertiary care academic medical center from June 2013 to September 2016. Patient demographics, stent information, and final diagnosis history were collected through chart review. Costs were determined using published reimbursement rates for Medicare. Results  Two hundred thirty-one stents from 175 patients were sent for cytologic analysis during the study period. Of the 62 stents obtained from patients ultimately diagnosed with malignancy, only one (1.6 %) had positive cytology for malignant cells, while the others were acellular/non-diagnostic (2/62, 3.2 %), negative (48/62, 77.4 %), or atypical (11/62, 17.7 %). The sensitivity of stent cytology for diagnosis of malignancy was 1.6 % (1/62). No cases were identified in which stent cytology changed clinical management. From a payer perspective, the mean estimated cost for each stent cytologic analysis is greater than $ 70.00. Conclusions  While stent cytologic analysis is a common clinical practice, the diagnostic yield and cost effectiveness of the practice must be reevaluated. With the rise of newer diagnostic technologies such as digital cholangioscopy and endoscopic ultrasound-guided fine-needle biopsy, it may be time to "think lean" and acknowledge a sunset for biliary stent cytology.

UroVysion Multi-Target Fluorescence in situ Hybridization Assay for the Detection of Malignant Bile Duct Brushing Specimens: A Comparison with Routine Cytology

OBJECTIVE

Routine bile duct brushing cytology is an important diagnostic tool in the evaluation of bile duct stricture. The purpose of this study was to evaluate the performance of the UroVysion fluorescence in situ hybridization (FISH) assay for the detection of malignant bile duct brushing specimens.

STUDY DESIGN

Thirty-five bile duct brushing specimens were included in the study. The FISH assay utilized the commercially available UroVysion probes. The indeterminate cytology results were considered as negative for statistical analysis.

RESULTS

Twenty-two of 35 patients were diagnosed as having malignancy based on tissue diagnosis or clinical progression of disease by image assessment. The sensitivity of routine cytology and FISH for the detection of malignancy was 14% (3/22) and 55% (12/22), respectively (p = 0.003). The specificity of routine cytology and FISH was 100% (13/13) and 62% (8/13), respectively (p = 0.025). The false-positive rate for routine cytology and FISH was 0% (0/13) and 38% (5/13), respectively.

CONCLUSIONS

Our study shows that FISH is significantly more sensitive than routine cytology for the detection of malignancy in bile duct brushing specimens. However, in our study, the specificity of FISH was poor compared to the excellent specificity of routine cytology. The compromised specificity of FISH may limit its utility in the detection of malignant bile duct brushing specimens.

How SpyGlass™ May Impact Endoscopic Retrograde Cholangiopancreatography Practice and Patient Management

INTRODUCTION

Cholangiopancreatoscopy with SpyGlass™ Direct Visualization System (SGDVS) is being used in specialized centers for improving the sensitivity of endoscopic retrograde cholangiopancreatography (ERCP) in patients with indeterminate pancreatobiliary strictures (PBS). The aims of this study were to report our initial experience with SGDVS in the evaluation of indeterminate PBS, and discuss the improvements of ERCP brought by this technique in our center.

METHODS

The usefulness of SGDVS in patients with indeterminate PBS (defined after nondiagnostic previous ERCP with brush cytology) was evaluated in a prospective observational cohort study conducted at a single tertiary biliopancreatic unit. The accuracy of diagnosis by the SGDVS visual findings, SGDVS-guided biopsy, technical success, image quality, change in patient management after the procedure, and complication rate were assessed.

RESULTS

In our single-center cohort, there were 13 SGDVS procedures for evaluating indeterminate PBS. Technical success, defined by the ability to progress with the SpyScope to the target lesion, was achieved in all the cases. The diagnostic accuracy of visual findings (87.5%) was superior to SGDVS-guided biopsy (55%). In 11 (85%) procedures, the image quality was considered good. The procedure permitted exclusion of malignancy and avoiding surgery in 9 patients (69%). There were no complications during the procedures. However, in the post-procedure monitoring, 3 patients developed acute pancreatitis (19%) and 2 patients developed acute cholangitis (13%).

CONCLUSION

The SGDVS can be considered useful in the context of indeterminate PBS. The intervention is associated with high procedural success and alters clinical outcome compared to conventional approaches.

Indeterminate biliary strictures: a simplified approach

Pre-operative evaluation of biliary strictures remains challenging. The dilemma that exists is how to balance the risk of failing to detect malignancy and the potential morbidity caused by unnecessary surgery in patients with benign etiologies. With emerging novel diagnostic modalities, this study aims to assess the efficacy of diagnostic techniques and facilitate a clinical approach to indeterminate biliary strictures. Areas covered: Conventional imaging modalities are crucial in identifying the location of a stricture and are helpful for choosing further diagnostic modalities. Utilization of endoscopic techniques, including endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS), is key in establishing a diagnosis. The emergence of novel diagnostic modalities, such as fluorescence in-situ hybridization (FISH), peroral cholangioscopy (POC), intraductal endoscopic ultrasound (IDUS) and confocal laser endomicroscopy (CLE), enhance the diagnostic yield in the evaluation of indeterminate biliary strictures. Expert commentary: More reliable and validated visual criteria for differentiating malignancy from benign biliary conditions, utilizing advanced imaging modalities such as POC and CLE, need to be established. It is of significance to further evaluate these novel diagnostic modalities through ongoing trials and to develop a diagnostic algorithm that reconciles cost-effectiveness with diagnostic accuracy.

Extracellular Vesicles in Bile as Markers of Malignant Biliary Stenoses

BACKGROUND & AIMS

Algorithms for diagnosis of malignant common bile duct (CBD) stenoses are complex and lack accuracy. Malignant tumors secrete large numbers of extracellular vesicles (EVs) into surrounding fluids; EVs might therefore serve as biomarkers for diagnosis. We investigated whether concentrations of EVs in bile could discriminate malignant from nonmalignant CBD stenoses.

METHODS

We collected bile and blood samples from 50 patients undergoing therapeutic endoscopic retrograde cholangiopancreatography at university hospitals in Europe for CBD stenosis of malignant (pancreatic cancer, n = 20 or cholangiocarcinoma, n = 5) or nonmalignant (chronic pancreatitis [CP], n = 15) origin. Ten patients with CBD obstruction due to biliary stones were included as controls. EV concentrations in samples were determined by nanoparticle tracking analyses. The discovery cohort comprised the first 10 patients with a diagnosis of pancreatic cancer, based on tissue analysis, and 10 consecutive controls. Using samples from these subjects, we identified a threshold concentration of bile EVs that could best discriminate between patients with pancreatic cancer from controls. We verified the diagnostic performance of bile EV concentration by analyzing samples from the 30 consecutive patients with a diagnosis of malignant (pancreatic cancer or cholangiocarcinoma, n = 15) or nonmalignant (CP, n = 15) CBD stenosis. Samples were compared using the Mann-Whitney test and nonparametric Spearman correlation analysis. Receiver operating characteristic area under the curve was used to determine diagnostic accuracy.

RESULTS

In both cohorts, the median concentration of EVs was significantly higher in bile samples from patients with malignant CBD stenoses than controls or nonmalignant CBD stenoses (2.41 × 10¹⁵ vs 1.60 × 10¹⁴ nanoparticles/L in the discovery cohort; P < .0001 and 4.00 × 10¹⁵ vs 1.26 × 10¹⁴ nanoparticles/L in the verification cohort; P < .0001). A threshold of 9.46 × 10¹⁴ nanoparticles/L in bile best distinguished patients with malignant CBD from controls in the discovery cohort. In the verification cohort, this threshold discriminated malignant from nonmalignant CBD stenoses with 100% accuracy. Serum concentration of EVs distinguished patients with malignant vs patients with nonmalignant CBD stenoses with 63.3% diagnostic accuracy.

CONCLUSIONS

Concentration of EVs in bile samples discriminates between patients with malignant vs nonmalignant CBD stenosis with 100% accuracy. Further studies are needed to confirm these findings. Clinical Trial registration no: ISRCTN66835592.

Cost utility of ERCP-based modalities for the diagnosis of cholangiocarcinoma in primary sclerosing cholangitis

BACKGROUND AND AIMS

Cholangiocarcinoma (CCA) is a leading cause of morbidity and mortality in patients with primary sclerosing cholangitis (PSC). Although several ERCP-based diagnostic modalities are available for diagnosing CCA, it is unclear whether one modality is more cost-effective than the others. The primary aim of this study was to compare the cost-effectiveness of ERCP-based techniques for diagnosing CCA in patients with PSC-induced biliary strictures.

METHODS

We performed a cost utility analysis to assess the net monetary benefit for accurately diagnosing CCA using 5 different diagnostic strategies: (1) ERCP with bile duct brushing for cytology, (2) ERCP with brushings for cytology and fluorescence in situ hybridization (FISH)-trisomy, (3) ERCP with brushings for cytology and FISH-polysomy, (4) ERCP with intraductal biopsy sampling, and (5) single-operator cholangioscopy (SOC) with targeted biopsy sampling. A Monte Carlo simulation assessed outcomes including quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Sensitivity analyses were also performed.

RESULTS

SOC with targeted biopsy sampling, as compared with ERCP with brushing for FISH-polysomy, produced an incremental QALY gain of .22 at an additional cost of $8562.44, resulting in a base case ICER of $39,277.25. Deterministic and probabilistic sensitivity analyses demonstrated that diagnosis with SOC was cost-effective at conventional willingness-to-pay thresholds of $50,000 and $100,000. SOC was the most cost-effective diagnostic strategy.

CONCLUSIONS

SOC with biopsy sampling is the most cost-effective diagnostic modality for CCA in PSC strictures.

Diagnosis of pancreaticobiliary malignancy by detection of minichromosome maintenance protein 5 in biliary brush cytology

Background:

Biliary brush cytology is the standard method of evaluating biliary strictures, but is insensitive at detecting malignancy. In pancreaticobiliary cancer minichromosome maintenance replication proteins (MCM 2–7) are dysregulated in the biliary epithelium and MCM5 levels are elevated in bile samples. This study aimed to validate an immunocolorimetric ELISA assay for MCM5 as a pancreaticobiliary cancer biomarker in biliary brush samples.

Methods:

Biliary brush specimens were collected prospectively at ERCP from patients with a biliary stricture. Collected samples were frozen at −80 °C. The supernatant was washed and lysed cells incubated with HRP-labelled anti-MCM5 mouse monoclonal antibody. Test positivity was determined by optical density absorbance. Patients underwent biliary brush cytology or additional investigations as per clinical routine.

Results:

Ninety-seven patients were included in the study; 50 had malignant strictures. Median age was 65 years (range 21–94) and 51 were male. Compared with final diagnosis the MCM5 assay had a sensitivity for malignancy of 65.4% compared with 25.0% for cytology. In the 72 patients with paired MCM5 assay and biliary brush cytology, MCM5 demonstrated an improved sensitivity (55.6% vs 25.0% P=0.0002) for the detection of malignancy.

Conclusions:

Minichromosome maintenance replication protein5 is a more sensitive indicator of pancreaticobiliary malignancy than standard biliary brush cytology.

Adult bile duct strictures: differentiating benign biliary stenosis from cholangiocarcinoma

Biliary epithelial cells preferentially respond to various insults under chronic pathological conditions leading to reactively atypical changes, hyperplasia, or the development of biliary neoplasms (such as biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and cholangiocarcinoma). Moreover, benign biliary strictures can be caused by a variety of disorders (such as IgG4-related sclerosing cholangitis, eosinophilic cholangitis, and follicular cholangitis) and often mimic malignancies, despite their benign nature. In addition, primary sclerosing cholangitis is a well-characterized precursor lesion of cholangiocarcinoma and many other chronic inflammatory disorders increase the risk of malignancies. Because of these factors and the changes in biliary epithelial cells, biliary strictures frequently pose a diagnostic challenge. Although the ability to differentiate neoplastic from non-neoplastic biliary strictures has markedly progressed with the advance in radiological modalities, brush cytology and bile duct biopsy examination remains effective. However, no single modality is adequate to diagnose benign biliary strictures because of the low sensitivity. Therefore, understanding the underlying causes by compiling the entire clinical, laboratory, and imaging data; considering the under-recognized causes; and collaborating between experts in various fields including cytopathologists with multiple approaches is necessary to achieve an accurate diagnosis.

A meta-analysis of the diagnostic value of detecting K-ras mutation in pancreatic juice as a molecular marker for pancreatic cancer

BACKGROUND

K-ras codon 12 mutation is one of the earliest genetic changes in the development of pancreatic cancer (PC) and accurate detection of K-ras mutations is gaining increasing attention in the field of molecular diagnosis.

METHODS

Original research articles which evaluated the diagnostic accuracy of K-ras mutation detection in PC were selected. Data were presented as forest plots and summary receiver operating characteristic curve analysis was used to summarize the overall test performance.

RESULTS

We assessed 16 studies from 15 published articles. The pooled sensitivity and specificity were 59% (95%CI: 54%-64%) and 87% (95%CI: 84%-89%), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.13 (95%CI: 2.73-6.25) and 0.42 (95%CI: 0.32-0.56), respectively, and the pooled diagnostic odds ratio was 13.66 (95% CI: 7.25-25.74).

CONCLUSIONS

Our results indicate that the analysis of K-ras mutations in pancreatic juice has a considerable diagnostic value in PC. Further studies with rigorous design, large sample size, and multi-regional co-operation are needed.

Evaluation of indeterminate biliary strictures

Biliary strictures frequently present a diagnostic challenge during pre-operative evaluation to determine their benign or malignant nature. A variety of benign conditions, such as primary sclerosing cholangitis (PSC) and IgG4-related sclerosing cholangitis, frequently mimic malignancies. In addition, PSC and other chronic biliary diseases increase the risk of cholangiocarcinoma and so require ongoing vigilance. Although traditional methods of evaluation including imaging, detection of circulating tumour markers, and sampling by endoscopic ultrasound and endoscopic retrograde cholangiopancreatography have a high specificity, they suffer from low sensitivity. Currently, up to 20% of biliary strictures remain indeterminate after pre-operative evaluation and necessitate surgical intervention for a definitive diagnosis. The discovery of novel biomarkers, new imaging modalities and advanced endoscopic techniques suggests that a multimodality approach might lead to better diagnostic accuracy.

Cost-effectiveness of the evaluation of a suspicious biliary stricture

BACKGROUND

Biliary stricture without mass presents diagnostic and therapeutic challenges because the poor sensitivity of the available tests and significant mortality and cost with operation.

METHODS

A decision model was developed to analyze costs and survival for 1) investigation first with endoscopic ultrasound (EUS) and fine needle aspiration, 2) investigation first with endoscopic retrograde cholangiopancreatography (ERCP) and brushing, or 3) surgery on every patient. The average age of someone with a biliary stricture was found to be 62-y-old and the rate of cancer was 55%. Incremental cost-effectiveness ratios (ICER) were calculated based on the change in quality adjusted life years (QALYs) and costs (US$) between the different options, with a threshold of $150,000 to determine the most cost-effective strategy. One-way, two-way, and probabilistic-sensitivity analysis were performed to validate the model.

RESULTS

ERCP results in 9.05 QALYs and a cost of $34,685.11 for a cost-effectiveness ratio of $3832.33. EUS results in an incremental increase in 0.13 QALYs and $2773.69 for an ICER of $20,840.28 per QALY gained. Surgery resulted in a decrease of 1.37 QALYs and increased cost of $14,323.94 (ICER-$10,490.53). These trends remained within most sensitivity analyses; however, ERCP and EUS were dependent on the test sensitivity.

CONCLUSIONS

In patients with a biliary stricture with no mass, the most cost-effective strategy is to investigate the patient before operation. The choice between EUS and ERCP should be institutionally dependent, with EUS being more cost-effective in our base case analysis.