789. EFFICACY AND SAFETY OF CRYOBALLOON-180 ABLATION FOR THE TREATMENT OF DYSPLASTIC BARRETT ESOPHAGUS: PRELIMINARY RESULTS FROM A PROSPECTIVE MULTICENTER STUDY

Abstract Background Cryoballoon-ablation is a relatively novel method for the eradication of dysplastic Barrett esophagus (BE). While the focal cryoballoon-ablation system has shown to be efficacious for BE of limited extent, the cryoballoon180-ablation system (CBAS180) is developed to treat longer BE segments by semi-circumferential ablation over 3cm, in a single step. A first-in-human study demonstrated the feasibility of CBAS180 treatment, yet the optimal dose needs to be determined. The current prospective, multicenter study, investigates CBAS180 at lower dosages for patients with dysplastic BE. Methods A total of 62 patients with ablation naïve BE (C≤3 and M≥1) will be enrolled in six Dutch Barrett expert centers. Treatment consists of a full circumferential ablation over 3 cm of length, using two semi-circumferential ablations at a dose of 1.2 mm/sec. Follow-up consisted of phone calls at days 1, 7 and 30, a symptom diary during 14 days, and an endoscopy after 3 months. Outcomes included (1) technical success rate; (2) BE regression percentage at follow-up scored by an independent adjudication committee; (3) incidence of adverse events; (4) post-procedural pain (scored on a scale of 0-10); and (5) post-procedural dysphagia (scored on a validated scale of 0-4). Follow-up treatment consisted of focal cryoballoon-ablation until complete eradication of visible BE was achieved, confirmed by biopsies from the neo-Z-line. Results So far, 25 patients (80% male; mean age 67) with a median BE length of C0M2 (p25-p75 C0-1M2-4) were included. Technical success rate was 92% (23/25; 95% CI 74-99%). In two patients, treatment was technically unsuccessful due to unstable positioning of the balloon (n=1) or a device malfunction (n=1). Median procedure time was 14 (p25-p75 11-16) 4) minutes and median ablation time was 5 (p25-p75 3-5) minutes. All 23 successfully treated patients completed follow-up endoscopy at 3 months. Median BE regression was 90% (p25-p75 75%-100%) evaluated by the independent adjudication committee. Overall, CBAS180 adverse event rate was 8% (2/23); one patient developed esophageal stricture (1/23; 4% [95% CI 1-16%]) resolved after a single endoscopic dilation. Another patient (1/23; 4% [95% CI 1-16%]) experienced post-procedural bleeding, with re-endoscopy without intervention. The CBAS180 procedure was well tolerated with low post-procedural pain (median 2 [p25-p75 1-4] at day 1 and 0 [p25-p75 0-1] at day 7) and dysphagia (56% and 70% of patients with score 0 at days 1 and 7, respectively) scores. So far, 22/23 (95%) patients were additionally treated with focal cryoballoon-ablation and 18/22 (82%) achieved a complete endoscopis and histologic eradication of BE after median 1 (p25-p75 1-3) treatment, the other 4 are still under treatment. After focal cryoballoon-ablation, 2/22 patients developed strictures, resolved after 1 and 2 endoscopic dilatations. Conclusion Based on these preliminary results, circumferential ablation with CBAS180 at 1.2 mm/sec, followed by focal cryoballoon-ablation, emerges as an effective and safe procedure for dysplastic BE eradication in the hands of expert endoscopists. Further avenues for exploration should encompass the assessment of multiple CBAS180 ablations stacked on top of each other in larger segments and the validation of outcomes in a larger patient cohort.