Combination of EUS-FNA and elastography (strain ratio) to exclude malignant solid pancreatic lesions: A prospective single-blinded study

Background:Negative results of EUS-FNA for solid pancreatic lesions (SPL) can be false ones. Combination with strain ratio (SR) may ensure a correct benign diagnosis of SPL. Aims:We prospectively evaluated the sensitivity rate of EUS-FNA and EUS elastography using the strain ratio method for diagnosing SPL. Methods:Thirty-eight patients with SPL identified by CT or MRI between January 2013 and November 2013 were included in our prospective study. EUS diagnoses were made using SR by an endosonographer who was blinded to all clinical information. In SPL with adequate cellularity, the results of EUS-FNA were combined with strain ratio to diagnose SPL and the diagnostic value was calculated. Results:Benign SPL were diagnosed in nine patients with surgical or guided-biopsy pathology (n=3) and benign cells from FNA with stable disease during the 12-month follow-up time (n=6). Using the best cut-off strain ratio level at 3.17, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rate of EUS elastography were 86.2%, 66.7%, 89.3%, 60%, and 81.6%, respectively. For the 28 patients who underwent EUS-FNA with results of adequate cellularity; EUS-FNA alone versus combination of results of cytology and SR provided sensitivity, specificity, PPV, NPV, and accuracy rate at 90% versus 95.2, 100% versus 71.4%, 100% versus 90.9%, 80% versus 83.3, and 92.9% versus 89.3%, respectively. Conclusions:In this prospective single-blinded study, the negative results of both EUS-FNA and SR were more reliable to exclude malignant SPL. The sensitivity of EUS elastography by SR was not superior to EUS-FNA. (c) 2015 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd