title: Clinical significance of observation without repeated radioiodine therapy in differentiated thyroid carcinoma patients with positive surveillance whole-body scans and negative thyroglobulin.
abstract: OBJECTIVE
  Currently, there is no consensus on the necessity of repeated radioiodine therapy (RAI) in patients who show iodine uptake in the thyroid bed on a diagnostic whole-body scan (DxWBS) despite undetectable thyroglobulin (Tg) levels after remnant ablation. The present study investigated the clinical outcomes of scan-positive, Tg-negative patients (WBS+Tg-) who did or did not receive additional RAI.
  
  
  METHODS
  We retrospectively reviewed 389 differentiated thyroid carcinoma patients who underwent a total thyroidectomy and received high-dose RAI from January 2003 through December 2005. The patients were classified according to surveillance DxWBS findings and TSH-stimulated Tg levels 6 to 12 months after the initial RAI.
  
  
  RESULTS
  Forty-four of the 389 patients (11.3%) showed thyroid bed uptake on a DxWBS despite negative Tg levels (WBS+Tg-). There was no difference in clinical and pathological parameters between WBS+Tg- and WBS-Tg- patients, except for an increased frequency of thyroiditis in the WBS+Tg- group. Among the 44 WBS+Tg- patients, 27 subjects were treated with additional RAI; 25 subjects showed no uptake in subsequent DxWBS. Two patients were evaluated only by ultrasonography (US) and displayed no persistent/recurrent disease. The other 17 patients received no further RAI; Eight patients and two patients showed no uptake and persistent uptake, respectively, on subsequent DxWBS. Six patients presented negative subsequent US findings, and one was lost to follow-up. Over the course of 53.2 ± 10.1 months, recurrence/persistence was suspicious in two patients in the treatment group.
  
  
  CONCLUSIONS
  There were no remarkable differences in clinical outcomes between observation and treatment groups of WBS+Tg- patients. Observation without repeated RAI may be an alternative management option for WBS+Tg- patients.
authors.affiliation: Department of Internal Medicine, The Catholic University of Korea School of Medicine, Seoul, Korea.
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Lim
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: O
authors.forename: Min-Hee
authors.initials: MH
authors.lastname: Kim
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyuk-Sang
authors.initials: HS
authors.lastname: Kwon
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Moo-Il
authors.initials: MI
authors.lastname: Kang
authors.forename: Bong-Yun
authors.initials: BY
authors.lastname: Cha
authors.forename: Kwang-Woo
authors.initials: KW
authors.lastname: Lee
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Son
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin