Single-center studies, which were retrospective and/or involved unblinded colonoscopists, have suggested that water exchange, but not water immersion, compared with air insufflation significantly increases the adenoma detection rate (ADR), particularly in the proximal and right colon. Head-to-head comparison of the three techniques with ADR as primary outcome and blinded colonoscopists has not been reported to date. In a randomized controlled trial with blinded colonoscopists, we aimed to evaluate the impact of the three insertion techniques on ADR. A total of 1224 patients aged 50 - 70 years (672 males) and undergoing screening colonoscopy were randomized 1:1:1 to water exchange, water immersion, or air insufflation. Split-dose bowel preparation was adopted to optimize colon cleansing. After the cecum had been reached, a second colonoscopist who was blinded to the insertion technique performed the withdrawal. The primary outcome was overall ADR according to the three insertion techniques (water exchange, water immersion, and air insufflation). Secondary outcomes were other pertinent overall and right colon procedure-related measures. Baseline characteristics of the three groups were comparable. Compared with air insufflation, water exchange achieved a significantly higher overall ADR (49.3 %, 95 % confidence interval [CI] 44.3 % - 54.2 % vs. 40.4 % 95 %CI 35.6 % - 45.3 %; = 0.03); water exchange showed comparable overall ADR vs. water immersion (43.4 %, 95 %CI 38.5 % - 48.3 %; = 0.28). In the right colon, water exchange achieved a higher ADR than air insufflation (24.0 %, 95 %CI 20.0 % - 28.5 % vs. 16.9 %, 95 %CI 13.4 % - 20.9 %; = 0.04) and a higher advanced ADR (6.1 %, 95 %CI 4.0 % - 9.0 % vs. 2.5 %, 95 %CI 1.2 % - 4.6 %; = 0.03). Compared with air insufflation, the mean number of adenomas per procedure was significantly higher with water exchange ( = 0.04). Water exchange achieved the highest cleanliness scores (overall and in the right colon). These variables were comparable between water immersion and air insufflation. The design with blinded observers strengthens the validity of the observation that water exchange, but not water immersion, can achieve significantly higher adenoma detection than air insufflation. Based on this evidence, the use of water exchange should be encouraged.Trial registered at ClinicalTrials.gov (NCT02041507).

Urban a Background. The management and prognosis of subepithelial tumors (SETs) of the upper gastrointestinal tract depend on the correct preoperative evaluation, including tissue diagnosis in selected cases. Several methods providing deep tissue sampling for cytological and/or histological examinations have been described but their diagnostic yield and precise position in the diagnostic algorithm remain to be established. This prospective randomized study aims to compare the Endosonography-Guided Fine-Needle Aspiration (EUS-FNA) to KeyHole Biopsy (KHB) in cytological or histological diagnostics of upper gastrointestinal SETs. Patients and Methods. This study was conducted in a single tertiary endoscopy center in Ostrava, Czech Republic between November 2010 and October 2015. Patients with endoscopically detected SETs of the upper gastrointestinal tract with a diameter ≥ 2 cm, were randomized to either the EUS-FNA with 22G needle, or to the Key Hole biopsy (forceps biopsy through mucosal incision) groups. The main study outcomes were success rate of tissue diagnostics and, in the cases of Gastrointestinal Stromal Tumours (GIST), possibility of determining mitotic activity. A cross-over examination was performed in situations where the first method had failed. Results. A total of 46 consecutive patients were randomized. Of these, 24 (52%) and 22 (48%) were randomized to EUS-FNA group and KHB arm, respectively. 5 SETs (11%) were detected in the esophagus, 40 (87%) in the stomach and 1 (2%) in the duodenum. The definitive diagnosis was established by the first sampling method in 42 (91%) patients, including 22 (92%) in the EUS-FNA group and 20 (91%) in the KHB group (P=0.999), and after a cross-over in another 3 (7%) patients. The most prevalent SET was GIST (70%). Although some mitotic activity could be observed in 11 patients, the mitotic index could be diagnosed in none of them. Of a total of 20 surgically treated patients, preoperative and postoperative tissue diagnosis corresponded in 19/20 (95%) cases, including 100% in FNA group and 91% in KHB group (P=0.999). No adverse events of tissue sampling occurred in the study. Conclusions. Deep tissue sampling by EUS-FNA and KHB are equally effective in the diagnostics of SETs of the upper gastrointestinal tract ≥ 2 cm. However, neither EUS-FNA nor KHB provided adequate tissue sample to determine mitotic index. Trial Registration: Clinicaltrials.gov (NCT02025244).

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EUS-FNA provides accurate diagnosis in 92% and has positive therapeutic impact in two-thirds of patients with solid pancreatic mass. Despite negative cytology, surgical exploration is recommended in clinical suspicion for pancreatic cancer and solid mass on EUS.

Compared with AI and WI, the superior ADR of WE offsets the drawback of a significantly longer insertion time. For quality improvement focused on increasing adenoma detection, WE is preferred over WI. The hypothesis that WE could lower the risk of interval colorectal cancers and related deaths should be tested.