title: Initial [18F]FDG PET/CT in high-risk DTC patients. A three-year follow-up.
abstract: In a previous paper, we published the impact of initial [18F]FDG PET/CT (FDG-PET/CT) in high-risk patients with differentiated thyroid cancer (DTC) and described the changes in therapy management. The aim of the present study was to evaluate the prognostic impact of the initial FDG-PET/CT on a patient's follow-up over three years and the rate of complete remission.
  
  
  METHODS
  This study included 109 DTC patients who underwent radioiodine treatment (RIT), including post-therapeutic whole-body scintigraphy with FDG-PET/CT and a follow-up over three years. The follow-up included high-resolution sonography of the neck and determination of serum Tg as well as Tg antibodies every six months. The results of initial FDG-PET/CT and whole-body scintigraphy were compared with the status after three years of follow-up.
  
  
  RESULTS
  24/109 patients (22%) presented FDG-positive lesions, 22/109 patients (20%) only iodine-positive lesions, and 63/109 patients (58%) neither FDG-positive nor iodine-positive lesions. After three years, 83/109 patients (76%) revealed full remission, 15/109 patients (14%) tumour persistence and 11/109 patients (10%) a progressive disease. The negative predictive value (NPV) was calculated for patients without FDG-positive lesions (NPV 85%) and patients without any lesions (NPV 91%) regarding full remission in the follow-up.
  
  
  CONCLUSIONS
  FDG-PET/CT has a high NPV (85% to 91%) in DTC patients regarding recurrence-free follow-up after three years. The change in patient management in patients with iodine-negative lesions can lead to a higher rate of full remissions in the follow-up after additional surgery. Therefore, FDG-PET/CT should be performed in all high-risk DTC patients in the context of the first RIT to improve patient management and risk stratification.
authors.affiliation: Dr. med. Marcus Ruhlmann, University Duisburg-Essen, Department of Nuclear Medicine, Hufelandstraße 55, 45122 Essen, Germany, Tel. +49/(0)201/723 20-81, Fax -98, marcus.ruhlmann@uk-essen.de.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ruhlmann
authors.forename: Ina
authors.initials: I
authors.lastname: Binse
authors.forename: Andreas
authors.initials: A
authors.lastname: Bockisch
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Rosenbaum-Krumme
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000401:mortality* / Q000517:prevention & control*; D000072078:Positron Emission Tomography Computed Tomography / Q000706:statistics & numerical data*; D015995:Prevalence; D011379:Prognosis; D019275:Radiopharmaceuticals; D018714:Radiotherapy, Adjuvant / Q000706:statistics & numerical data; D012074:Remission Induction; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Differentiated thyroid cancer; FDG-PET/CT; follow-up; iodine negative; radioiodine therapy; thyroid cancer