title: Locoregional control of metastatic well-differentiated thyroid cancer by ultrasound-guided radiofrequency ablation.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided radiofrequency ablation (RFA) in the control of metastatic well-differentiated thyroid carcinoma in patients for whom surgery is not feasible.
  
  
  METHODS
  Between December 2004 and June 2008, 12 metastatic differentiated thyroid carcinomas (mean diameter, 13.8 mm; range, 4-28 mm) in 10 patients (six women, four men; mean age, 44.8 years) were treated with RFA. The inclusion criteria for RFA were fewer than three metastatic tumors confirmed with ultrasound-guided fine-needle aspiration biopsy, no metastatic tumor beyond the neck at RFA, and infeasibility of surgery. A radiofrequency generator and 18-gauge internally cooled electrodes with a 7-cm shaft length and 0.5- and 1-cm active tips were used depending on the size of the targeted tumors. Ten of the 12 metastatic tumors (83%) were treated in a single session of RFA, and the other two required two sessions. The ablation time ranged from 60 to 900 seconds.
  
  
  RESULTS
  After treatment, the mean largest diameter decreased significantly from 13.8 ± 7.0 mm to 3.3 ± 3.9 mm (p = 0.002), as did mean volume, from 55.5 ± 50.3 mm(3) to 5.7 ± 9.3 mm(3) (p = 0.002). At the last follow-up evaluation, the serum thyroglobulin concentration had decreased in 7 of 10 patients. One patient had dysphonia immediately after RFA of a left surgical bed.
  
  
  CONCLUSIONS
  Although surgery is the standard treatment of locally metastatic thyroid cancer, RFA is effective for locoregional control of metastatic well-differentiated thyroid carcinoma in patients for whom surgery is infeasible.
authors.affiliation: Department of Radiology, Thyroid Center, Daerim St. Mary's Hospital, Seoul, Korea. radbaek@naver.com
authors.forename: Jung Hwan
authors.initials: JH
authors.lastname: Baek
authors.forename: Yoon Suk
authors.initials: YS
authors.lastname: Kim
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Sung
authors.forename: Hoon
authors.initials: H
authors.lastname: Choi
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional