title: Cryospray ablation using pressurized CO2 for ablation of Barrett's esophagus with early neoplasia: early termination of a prospective series.
abstract: BACKGROUND
  Cryotherapy is a relatively novel ablation modality for the endoscopic ablation of Barrett's esophagus (BE). Data on the use of pressurized carbon dioxide (CO2) gas for cryoablation are scarce.
  
  
  OBJECTIVE
  To determine the efficacy and safety of cryospray ablation using pressurized CO2 gas in the treatment of BE with early neoplasia.
  
  
  METHODS
  In this prospective single center case series, we aimed to include 30 patients with BE and early neoplasia. Nodular neoplastic lesions were treated with endoscopic mucosal resection (EMR). Residual BE mucosa was treated with cryospray ablation every 4 weeks until the complete BE segment was eliminated or up to seven treatment sessions. If no reduction of the BE segment was observed after two subsequent treatment sessions, cryoablation was terminated. Patients were contacted at days 1 and 4 post-treatment to evaluate the level of discomfort. Endoscopic and histologic follow-up evaluations were performed up to 24 months post-treatment.
  
  
  RESULTS
  After the inclusion of 10 patients, insufficient effect of cryoablation was observed, resulting in early termination of the study. In total, seven patients with intramucosal carcinoma (IMC) and three with high grade dysplasia (HGD) were included. Prior EMR was performed in nine patients. A median of 2.5 (IQR 2.0 - 4.0) cryoablation sessions were performed. At 6 months of follow-up, complete eradication of intestinal metaplasia was observed in 11 % (1 /9; one patient died, not treatment or disease related) of the patients and complete eradication of dysplasia in 44 % (4 /9). In three patients, HGD or IMC was detected during follow-up, and was endoscopically treated. Apart from a gastric perforation as a result of gastric distension caused by CO2 gas during the first treatment, cryospray treatments were well tolerated.
  
  
  CONCLUSIONS
  After a short learning curve, cryoablation using CO2 gas was found to be a safe and well tolerated treatment modality. However, in our experience, the efficacy of CO2 cryoablation combined with EMR for nodular lesions is disappointing for the treatment of BE associated neoplasia.
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Romy E
authors.initials: RE
authors.lastname: Verbeek
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Vleggaar
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Fiebo J
authors.initials: FJ
authors.lastname: Ten Kate
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Jantine W P M
authors.initials: JW
authors.lastname: van Baal
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Siersema