Comparison of the Modified Wet Suction and Dry Suction Techniques in EUS-FNA for Solid Lesions: A Prospective, Multicenter, Randomised Controlled Trial

Background: The optimal sampling techniques for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) remain unclear and have not been standardized. The aim of the study was to compare modified wet suction technique (MWST) and dry suction technique (DRST) for sampling the solid lesions in the pancreas, mediastinum, and abdomen. Methods: We performed a randomised controlled trial at four tertiary care centers in China. Consecutive patients with solid lesions referred for EUS-FNA were randomised in a ratio of 1:1 to receive either DRST or MWST as the first pass. For Group A, the pass sequence was DRST - MWST - DRST - MWST versus MWST - DRST - MWST - DRST for Group B. The outcome measures were the diagnostic yield and specimen quality. Findings: Between May 2016 and January 2018, 364 patients were screened for eligibility. 296 patients were recruited, 269 of whom (134 in Group A versus 135 in Group B) completed the trial. We demonstrated that the MWST group had a significantly better overall histological diagnostic accuracy (84·85%) than DRST group (73·19%, P =0·0013) for all solid lesions (n=269). In subgroup analysis, the MWST group reached a 91·59% histological diagnostic accuracy for non-pancreatic lesions (n=108). Furthermore, the MWST provided better specimen adequacy and less blood contamination than DRST. Interpretation: In this prospective study of sampling solid masses, we found that using MWST resulted in significantly better histological diagnostic accuracy and specimen quality than DRST. For many institutions where rapid on-site evaluation is not routinely available, the MWST within 2 passes of FNA reached a definitive histological diagnosis with no requirement of fine needle biopsy. Trial Registration: The study is registered on ClinicalTrials.gov (NCT02789371) and is completed. Funding Statement: National Natural Science Foundation of China. Declaration of Interests: All authors have declared that no competing interests exist. Ethics Approval Statement: The study was approved by the institutional review boards of all participating centers. Patients provided informed consent for participation in the study.