title: Ethanol ablation of predominantly cystic thyroid nodules: evaluation of recurrence rate and factors related to recurrence.
abstract: OBJECTIVE
  To evaluate recurrence rate and associated risk factors for recurrence after ethanol ablation (EA) in patients with predominantly cystic thyroid nodules.
  
  
  METHODS
  This observational study was approved by the Ethics Committee of the Institutional Review Board and informed consent for procedures was obtained. From April 2009 to April 2013, 107 consecutive patients with predominantly cystic nodules were treated using EA. Recurrence was defined as nodules showing a residual solid portion with internal vascularity, cosmetic problems remaining, or persistent symptoms, and patients who requested additional therapy to resolve their symptomatic or cosmetic problems. Delayed recurrence was defined as treated nodules that showed no recurrent features at 1 month, but showed newly developed recurrent features during the longer follow-up period. Multivariate analysis was used for variables to demonstrate the independent factors related to volume reduction.
  
  
  RESULTS
  One month after EA, 18.7% of patients (20/107) showed recurrence. Among 87 patients with non-recurrence, 24.1% (21/87) showed delayed recurrence. The total recurrence rate was 38.3% (41/107). Patients with recurrence (n = 41) were treated using radiofrequency ablation (n = 28), second EA (n = 4), and refused further treatment (n = 9). These patients responded well to repeat EA and radiofrequency ablation. Multivariate analysis demonstrated that the initial nodule volume (>20 ml; p < 0.036) and vascularity (grade >1; p < 0.049) were independent predictors of volume reduction at last follow-up.
  
  
  CONCLUSIONS
  The results revealed that although EA seemed to be effective during the initial period, delayed recurrence should be considered during longer-term follow-up. The independent predictors of recurrence were initial volume (>20 ml) and vascularity.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: C H
authors.initials: CH
authors.lastname: Suh
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea. Electronic address: radbaek@naver.com.
authors.forename: J H
authors.initials: JH
authors.lastname: Baek
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea; Department of Radiology, Ajou University School of Medicine, Wonchon-Dong, Yeongtong-Gu, Suwon 443-380, Republic of Korea.
authors.forename: E J
authors.initials: EJ
authors.lastname: Ha
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Radiology, Chung-Ang University College of Medicine, 224-1, Heukseok-dong, Dongjak-gu, Seoul 156-755, Republic of Korea.
authors.forename: J K
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: K-W
authors.initials: KW
authors.lastname: Chung
authors.affiliation: Department of Endocrinology and Metabolism, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: T Y
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Department of Endocrinology and Metabolism, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: W B
authors.initials: WB
authors.lastname: Kim
authors.affiliation: Department of Endocrinology and Metabolism, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Republic of Korea.
authors.forename: Y K
authors.initials: YK
authors.lastname: Shong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods; D002648:Child; D003560:Cysts / Q000000981:diagnostic imaging / Q000628:therapy*; D000431:Ethanol / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D012307:Risk Factors; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000628:therapy*; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods; D055815:Young Adult
chemical_list: D000431:Ethanol