Comparison of liquid-based cytology with conventional smear cytology for EUS-guided fine-needle aspiration of solid pancreatic masses: prospective randomized noninferiority study

摘要

Background and Aims<br/>There is limited data on the efficacy of liquid-based cytology (LBC) for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) specimens. We aimed to evaluate the diagnostic efficacy of LBC for solid pancreatic neoplasms compared with conventional smears (CS).<br/>Methods<br/>In this randomized, crossover, noninferiority trial, we randomly assigned (1:1) patients with suspected pancreatic cancer to either LBC or CS groups. Aspirates from the first needle pass were processed by one method, aspirates from the second pass by the other method, and specimens from the last pass were processed as core biopsies. The primary endpoint was the diagnostic efficacy of each method, with the final diagnosis as the gold standard. A noninferiority margin of -10% was assumed. This trial is registered with ClinicalTrials.gov, number NCT03606148.<br/>Results<br/>Of 170 randomized patients, 165 were classified as “malignant” and 5 as “benign.” Unsatisfactory samples were less frequent in LBC (1.78%) compared with CS (5.33%). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of LBC versus CS were 88.0% versus 83.8% (p=0.276), 87.7% versus 83.2% (p=0.256), 100% versus 100% (p=0.999), 100% versus 100% (p=0.999), and 16.7% versus 16.1% (p=0.953). A bloody background was significantly more frequent in CS (CS: 85.2%, LBC: 1.8%; p<0.001), whereas the nuclear features were similar for both groups.<br/>Conclusions<br/>The diagnostic utility of LBC was comparable with that of CS. The cytomorphologic features did not significantly differ between the 2 methods, and the reduced bloody backgrounds allowed better visibility in LBC method.

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