title: The role of FDG-PET in localization of recurrent lesions of differentiated thyroid cancer (DTC) in patients with asymptomatic hyperthyroglobulinemia in a real clinical practice.
abstract: BACKGROUND
  Available methods, including serum thyroglobulin (Tg) measurement and whole-body scan (WBS) performed after radioiodine administration, allow for a precise diagnostics in differentiated thyroid cancer (DTC). However, some asymptomatic patients demonstrate negative WBS despite a high Tg serum concentration. In these subjects, fluorodeoxyglucose-positron emission tomography (FDG-PET) should be considered. The primary aim of our study was to evaluate a diagnostic value of FDG-PET in asymptomatic hyperthyroglobulinemia. The secondary one was to determine a prognostic value of a negative FDG-PET result in DTC patients with elevated Tg level.
  
  
  METHODS
  One hundred and ten FDG-PET/CT scans were retrospectively analyzed, 85 scans were done under TSH stimulation and 25 on LT4 suppressive therapy. Follow-up ranged between 4 and 9 years.
  
  
  RESULTS
  The first FDG-PET/CT detected cancer foci in 49 subjects with a global sensitivity of 45%. When the sensitivity was evaluated with reference to TSH stimulation and suppression, its values were 50 and 28% respectively. In 42 patients, FDG-PET failed to diagnose the reason for elevated Tg level. During further follow-up, in 17 of them, DTC recurrence was detected by other methods (CT, MRI, US). Fourteen subjects with asymptomatic hyperthyroglobulinemia were free of DTC progression for at least 4 years.
  
  
  CONCLUSIONS
  FDG-PET in DTC patients with asymptomatic hyperthyroglobulinemia constitutes a valuable diagnostic tool. Negative FDG-PET demonstrated a limited prognostic significance, as only every third patient did not show DTC progression. Moreover, negative FDG-PET does not justify less strict DTC monitoring, because it is related to 40% risk of relapse during the 5-year follow-up.
authors: Nuclear Medicine and Endocrine Oncology Department akukulska@io.gliwice.pl.
authors: A
authors: A
authors: Kukulska
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: J
authors: J
authors: Krajewska
authors: Department of Epidemiology and Silesia Cancer RegistryM.Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.
authors: Z
authors: Z
authors: Kołosza
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: E
authors: E
authors: Paliczka-Cies Lik
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: Z
authors: Z
authors: Puch
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: E
authors: E
authors: Gubała
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: A
authors: A
authors: Król
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: M
authors: M
authors: Kalemba
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: A
authors: A
authors: Kropin Ska
authors: Nuclear Medicine and Endocrine Oncology Department.
authors: B
authors: B
authors: Jarząb
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography; D011379:Prognosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging*; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin