title: Empiric high-dose 131-iodine therapy lacks efficacy for treated papillary thyroid cancer patients with detectable serum thyroglobulin, but negative cervical sonography and 18F-fluorodeoxyglucose positron emission tomography scan.
abstract: BACKGROUND
  Some patients with elevated serum thyroglobulin (Tg) but a negative diagnostic whole body scan (WBS) after initial therapy for differentiated thyroid carcinoma may benefit from empirical radioactive iodine (RAI) therapy. However, previous studies enrolled patients with negative diagnostic WBS, regardless of neck ultrasonography (USG) and/or (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), which have become the preferred diagnostic procedures in such patients.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the usefulness of empirical RAI therapy in patients with elevated stimulated Tg level and negative USG/FDG-PET findings after initial therapy for papillary thyroid carcinoma (PTC).
  
  
  METHODS
  This comparative study enrolled 39 patients with elevated stimulated Tg, negative diagnostic WBS, and negative USG/FDG-PET 1 yr after initial treatment. Empirical RAI therapy was performed in 14 patients (treatment group), whereas 25 patients were followed up without therapy (control group).
  
  
  RESULTS
  There was no significant between-group difference in basal clinicopathological parameters. None of the 14 patients in the treatment group showed iodine uptake on posttreatment WBS. Five of 14 patients (36%) in the treatment group and eight of 25 (32%) in the control group had recurrence during the median 37 months of follow-up (P = 0.99). Changes in serum stimulated Tg concentrations did not differ between the two groups.
  
  
  CONCLUSIONS
  Empirical RAI therapy and posttreatment WBS were not useful diagnostically or therapeutically in patients with positive serum stimulated Tg if such patients had negative USG and negative FDG-PET findings after initial treatment of PTC.
authors.affiliation: Department of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea. kimwb@amc.seoul.kr
authors.forename: Won Gu
authors.initials: WG
authors.lastname: Kim
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Ryu
authors.forename: Eui Young
authors.initials: EY
authors.lastname: Kim
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Jung Hwan
authors.initials: JH
authors.lastname: Baek
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Yoon
authors.forename: Suck Joon
authors.initials: SJ
authors.lastname: Hong
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Kim
authors.forename: Tae Yong
authors.initials: TY
authors.lastname: Kim
authors.forename: Won Bae
authors.initials: WB
authors.lastname: Kim
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000097:blood / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D002648:Child; D004307:Dose-Response Relationship, Radiation; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012008:Recurrence; D018709:Statistics, Nonparametric; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D016896:Treatment Outcome; D014463:Ultrasonography; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin