title: Predictors for postoperative esophageal stricture after balloon-based radiofrequency ablation for early esophageal squamous neoplasia: a multicenter validation study.
abstract: BACKGROUND
  Endoscopic radiofrequency ablation (RFA) is a rapidly evolving therapeutic modality for early flat esophageal squamous cell neoplasms (ESCNs), but the risk factors for postoperative stricture have not been elucidated. The objective of this study was to identify and validate a predictor for post-RFA stenosis.
  
  
  METHODS
  We consecutively enrolled patients with flat-type 'large' (length no less than 3 cm extending no less than half the circumference of the esophagus), early ESCNs, treated with balloon-based RFA (12 J/cm(2)-clean-12 J/cm(2) regimen). The tumor and technical factors for postoperative stricture were investigated and we validated the results externally with a society-based multicenter cohort using the same ablation regimen.
  
  
  RESULTS
  A total of 51 patients were enrolled (30 in the development set and 21 in the validation set). The complete remission rate at 12 months was 93%, and the rates of perforation and postoperative stenosis were 0% and 17%, respectively. Patients with post-RFA stenosis had a significantly larger longitudinal tumor size (mean 115 versus 61 mm, p = 0.003). There were no significant differences in age, body mass index, tumor circumferential extension, pretreatment histological grade, treatment efficacy or size of balloon catheter between the groups with or without stenosis. The optimal cut-off value was set as 9 cm to predict post-RFA stenosis by receiver operating characteristic curve [area under curve (AUC) = 0.881], which was then confirmed to be a reliable predictor by multivariate analysis (odds ratio, 12.7, 95% confidence interval, 1.18-136.28, p = 0.03) and have a good predictive performance in the validation set (AUC = 0.876).
  
  
  CONCLUSIONS
  The most frequent adverse event of RFA was esophageal stenosis, for which the longitudinal tumor size was a significant predictive factor. Early intervention or prevention for stricture should be applied for those with long segment (⩾9 cm) ESCNs.
authors.affiliation: Department of Internal Medicine, Da Hospital/I-Shou University, Kaohsiung, Taiwan.
authors.forename: Wen-Lun
authors.initials: WL
authors.lastname: Wang
authors.affiliation: Department of Pathology, E-Da Hospital/I-Shou University, Kaohsiung, Taiwan.
authors.forename: I-Wei
authors.initials: IW
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Chien-Chuan
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, National Cheng Kung University Medical Center, Tainan, Taiwan.
authors.forename: Wei-Lun
authors.initials: WL
authors.lastname: Chang
authors.affiliation: Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan.
authors.forename: Yin-Yi
authors.initials: YY
authors.lastname: Chu
authors.affiliation: Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Ping-Hsiu
authors.initials: PH
authors.lastname: Wu
authors.affiliation: Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Wei-Chen
authors.initials: WC
authors.lastname: Tai
authors.affiliation: Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan.
authors.forename: Po-Yueh
authors.initials: PY
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, Chimei Medical Center, Tainan, Taiwan.
authors.forename: Ping-Hsin
authors.initials: PH
authors.lastname: Hsieh
authors.affiliation: Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan.
authors.forename: Chen-Shuan
authors.initials: CS
authors.lastname: Chung
authors.affiliation: Department of Internal Medicine, Da Hospital/I-Shou University, Kaohsiung, Taiwan.
authors.forename: Chi-Yang
authors.initials: CY
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, Da Hospital/I-Shou University, Kaohsiung, Taiwan.
authors.forename: Jaw-Town
authors.initials: JT
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, National Taiwan University, No. 1, Changde St., Zhongzheng Dist., Taipei City 10048, Taiwan.
authors.forename: Hsiu-Po
authors.initials: HP
authors.lastname: Wang
authors.affiliation: Department of Internal Medicine, E-Da Hospital/I-Shou University, No.1 Yida Road, Jiaosu Village, Yanchao District, Kaohsiung City 82445, Taiwan.
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Lee
keywords: adverse event; endoscopic ultrasound; esophageal squamous cell neoplasia; radiofrequency ablation; stricture