title: Combined use of radioiodine therapy and radiofrequency ablation in treating postsurgical thyroid remnant of differentiated thyroid carcinoma.
abstract: OBJECTIVE
  To determine whether postoperative radioiodine (RAI) combined with radiofrequency ablation (RFA) is an effective, safe, and feasible method for elimination of excessive postsurgical thyroid remnant for differentiated thyroid carcinoma (DTC).
  
  
  METHODS
  We took a prospective study and treated 12 DTC patients (4 males, 8 females, age 20-78 years) who underwent thyroidectomy for RFA followed by 131 I ablation. The pretreatment requires iodine-free diet and thyroid hormone withdrawal for 3-4 week. All the patients showed the level of serum thyroid-stimulating hormone (TSH) <30 mU/L, and obvious thyroid remnant in 99m Technetium (99m Tc) imaging. Serum TSH level was determined 1 day before RFA and on days 1, 7, 14 after RFA, and 99m Tc imaging was performed on day 14 after RFA. Subsequently, the patients were given an oral dosage of 3700 MBq 131 I for remnant ablation, and posttreatment whole body scan was performed on day 5 after ablation. Efficacy evaluation was done 4-6 months after treatment. The changes of variants before and after RFA were analyzed using Wilcoxon signed rank sum test.
  
  
  RESULTS
  Serum TSH was <30 μIU/ml (mean value 10.27 ± 6.16 μIU/ml) before RFA, and increased to more than 30 μIU/ml (34.73 ± 3.93 μIU/ml) 2 weeks later (P = 0.002, Wilcoxon rank sum test). The 99m Tc uptake ratio on day 14 postRFA was (0.31 ± 0.12)%, which is significantly lower than before RFA (0.80 ± 0.16)% (P = 0.002, Wilcoxon rank sum test). The success rate of thyroid remnant ablation was 91.7% (11/12), which was assessed 4-6 months after treatment. All patients reported neck discomfort and some are self-limiting, with no hoarseness, choking, or radiation thyroiditis symptoms. Five patients had puncture area pain, among which one patient had neck edema, which was relieved after prednisone treatment.
  
  
  CONCLUSIONS
  Combined use of RAI therapy and radiofrequency ablation in treating excessive postsurgical thyroid remnant of DTC can be an effective approach and avoids re-operation. Long-term efficacy monitoring would further determine its feasibility.
authors.forename: Bin
authors.initials: B
authors.lastname: Long
authors.affiliation: Department of Nuclear Medicine, Zhejiang Cancer Hospital, Hangzhou, Zhejiang Province 310022, People's Republic of, China.
authors.forename: Linfa
authors.initials: L
authors.lastname: Li
authors.forename: Lifang
authors.initials: L
authors.lastname: Yao
authors.forename: Shoucong
authors.initials: S
authors.lastname: Chen
authors.forename: Heqing
authors.initials: H
authors.lastname: Yi
authors.forename: Xuemei
authors.initials: X
authors.lastname: Ye
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010212:Papilloma / Q000097:blood / Q000000981:diagnostic imaging / Q000628:therapy*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use*; D013670:Sodium Pertechnetate Tc 99m / Q000493:pharmacokinetics; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000628:therapy*; D013972:Thyrotropin / Q000097:blood; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D013972:Thyrotropin; D013670:Sodium Pertechnetate Tc 99m