Prognostic Role of 18F-FDG PET/CT in the Postoperative Evaluation of Differentiated Thyroid Cancer Patients. (February 2015)

• Record Type: Journal Article
• Authors: Pace, Leonardo; Klain, Michele; Salvatore, Barbara; Nicolai, Emanuele; Zampella, Emilia; Assante, Roberta; Pellegrino, Teresa; Storto, Giovanni; Fonti, Rosa; Salvatore, Marco
• Is Part Of: Clinical nuclear medicine. Volume 40:Number 2(2015)
• Publication Date: 2015-02
• Subjects: FDG PET/CT -- differentiated thyroid cancer -- progression-free survival; Nuclear medicine -- Periodicals; Radioisotope scanning -- Periodicals; Nuclear Medicine -- Periodicals; 616.07575
• DOI: 10.1097/RLU.0000000000000621
• Languages: English
• ISSNs: 0363-9762

Abstract

Abstract : Purpose: The aim of this study was to evaluate the role of 18 F-FDG PET/CT performed after surgery but before radioiodine therapy in patients with differentiated thyroid cancer. Procedures: FDG PET/CT was performed off l-thyroxine in 60 newly diagnosed differentiated thyroid cancer patients. Clinical and hematological evaluation as well as high-resolution neck ultrasound were performed. All patients underwent a complete follow-up (range, 6-67 months; mean [SD], 31.7 [20.6] months). The date of recurrence or the most recent office visit was recorded. Progression-free survival (PFS) is the primary end point of this study. Analysis was performed by Cox proportional hazards model. Survival curves were generated using Kaplan-Meier estimates, and the log-rank test was used to assess significance. Results: FDG PET/CT was negative in 63% of patients, 20% had FDG thyroid bed uptake, 5% distant metastases, and 12% lymph node FDG uptake. In patients with positive FDG PET/CT scan (ie, those with distant metastases or lymph node uptake), a higher rate of recurrence was observed (50% vs 6%, P < 0.05). Thyroglobulin, neck ultrasound, stage, and FDG PET/CT correlated with PFS at univariate analysis. At multivariate analysis, only thyroglobulin and FDG PET/CT continued to be predictors of PFS. Patients with a negative FDG PET/CT scan have a better PFS either in the whole group or in those with elevated thyroglobulin level (both >2 ng/mL and >10 ng/mL). Conclusions: FDG PET/CT was abnormal in 17% of patients. Moreover, FDG PET/CT has an independent prognostic role, with a better PFS in patients with a negative scan.