sup 18^F-FDG uptake as a prognostic variable in primary differentiated thyroid cancer incidentally detected by PET/CT: a multicentre study

• Published in: European journal of nuclear medicine and molecular imaging 2014-08, Vol.41 (8), p.1482
• Main Authors: Piccardo, Arnoldo, Puntoni, Matteo, Bertagna, Francesco, Treglia, Giorgio, Foppiani, Luca, Arecco, Federico, Giubbini, Raffaele, Naseri, Mehrdad, Cistaro, Angelina, Cabria, Manlio, Bardesono, Francesca, Ceriani, Luca, Orlandi, Fabio, Giovanella, Luca
• Format: Article
• Language: English
• Subjects: Medical diagnosis; Medical prognosis; Nuclear medicine; Thyroid cancer; Tomography
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-014-2774-y

Our aim was to investigate the association between ^sup 18^F-fluorodeoxyglucose (FDG) uptake and event-free survival in patients in whom a differentiated thyroid cancer (DTC) was detected by ^sup 18^F-FDG positron emission tomography (PET)/CT. Among 884 focal ^sup 18^F-FDG PET thyroid incidentalomas referred to our 4 Nuclear Medicine Departments, we investigated 54 patients in whom a DTC was confirmed and a clinical follow-up was available. The ratio between maximum standardized uptake value (SUV^sub max^) of DTC and SUV^sub mean^ of the liver (SUV ratio) was recorded for each scan. All patients underwent total thyroidectomy and ^sup 131^I remnant ablation. After a median follow-up of 39 months we assessed the outcome. The association between disease persistence/progression, ^sup 18^F-FDG uptake and other risk factors (T, N, M and histological subtype) was evaluated through univariate and multivariate analyses. Of the 54 patients, 39 achieved complete remission. The remaining 15 showed persistence/progression of disease. High ^sup 18^F-FDG uptake, i.e. SUV ratio >=3, showed a low positive predictive value (48 %). Low ^sup 18^F-FDG uptake (SUV ratio