Elsevier

Gastrointestinal Endoscopy

Volume 76, Issue 5, November 2012, Pages 953-961
Gastrointestinal Endoscopy

Original article
Clinical endoscopy
Diagnostic accuracy of quantitative EUS elastography for discriminating malignant from benign solid pancreatic masses: a prospective, single-center study

https://doi.org/10.1016/j.gie.2012.05.034Get rights and content

Background

Recent data suggest that quantitative EUS elastography, a novel technique that allows real-time quantification of tissue stiffness, can accurately differentiate malignant from benign solid pancreatic masses.

Objective

To externally validate the diagnostic utility of this technique in an independent cohort.

Design and Setting

Prospective, single-center study.

Patients, Interventions, and Methods

A total of 104 patients with evidence of a solid pancreatic mass on cross-sectional imaging and/or endosonography underwent 111 quantitative EUS elastography procedures. Multiple elastographic measurements of the mass lesion and soft-tissue reference areas were undertaken, and the corresponding strain ratios (SRs) were calculated. The final diagnosis was based on pancreatic cytology or histology.

Main Outcome Measurements

The area under the receiver-operating characteristic curve, sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of quantitative EUS elastography for discriminating malignant from benign pancreatic masses.

Results

The final diagnoses were primary pancreatic carcinoma (71.2%), neuroendocrine tumor (10.6%), metastatic cancer (1.9%), and pancreatitis (16.3%). Malignant masses had a higher SR (P = .01) and lower mass elasticity (P = .003) than inflammatory ones. The areas under the receiver-operating characteristic curve for the detection of pancreatic malignancy of both SR and mass elasticity (0.69 and 0.72, respectively) were less favorable than reported recently. At the cut points providing the highest accuracy in this cohort (4.65 for SR and 0.27% for mass elasticity), quantitative EUS elastography had a sensitivity of 100.0% and 95.7%, specificity of 16.7% and 22.2%, positive predictive value of 86.1% and 86.4%, negative predictive value of 100.0% and 50.0%, and overall accuracy of 86.5% and 83.8%, respectively.

Limitations

Relatively small number of patients with benign disease.

Conclusion

In the largest single-center study to date, the diagnostic utility of quantitative EUS elastography for discriminating pancreatic masses was modest, suggesting that it may only supplement rather than supplant the role of pancreatic tissue sampling in the future.

Section snippets

Patients and methods

The Freeman Hospital serves as a tertiary referral center of hepatobiliary and pancreatic surgery for the North East region of England with a population of approximately 3.5 million, undertaking approximately 750 pancreaticobiliary EUS procedures per year. EUS, EUS-FNA, and qualitative tissue elastography are standard procedures in clinical practice and are used routinely at our center for the assessment of pancreatic masses. In accordance with the UK National Research Ethics Service

Clinical characteristics

A total of 104 individuals (median age 67 years, 57 males) underwent a total of 111 quantitative EUS elastography assessments of a pancreatic mass (Table 1). Seventeen of the masses (16.3%) proved secondary to pancreatitis (one of which being autoimmune), whereas the remainder were related to malignancy, the final diagnosis being primary pancreatic carcinoma in 71.2%, neuroendocrine tumor in 10.6%, and metastatic cancer in 1.9%. The median mass size was 3 cm, with the most common location being

Discussion

In this prospective external validation study of quantitative EUS elastography for the differentiation of malignant from benign solid pancreatic masses using both SR and mass elasticity analysis, we observed good sensitivity but less favorable specificity, NPV, overall accuracy and diagnostic discrimination than those originally reported by Iglesias-Garcia et al.17 Re-deriving the optimal cutoff values from our cohort resulted in a modest improvement in overall accuracy. The suboptimal

Conclusion

We report herein the largest single-center study of quantitative EUS elastography in the differential diagnosis of solid pancreatic masses. The accuracy and specificity are less favorable than recently reported, although some improvement in diagnostic performance is achieved when internally derived cutoff points are used. We believe that this technique is likely to supplement rather than replace the role of pancreatic tissue sampling in the future.

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    DISCLOSURE: The authors disclosed no financial relationships relevant to this publication.

    If you would like to chat with an author of this article, you may contact Dr Dawwas at [email protected].

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