Prognostic Role of 2-[18F]FDG PET/CT Metabolic Volume Parameters in Patients Affected by Differentiated Thyroid Carcinoma with High Thyroglobulin Level, Negative 131I WBS and Positive 2-[18F]-FDG PET/CT

Abstract

The clinical and prognostic role of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) in the study of patients affected by differentiated thyroid carcinoma (DTC) with positive serum thyroglobulin (Tg) level and negative [131I] whole-body scan ([131I]WBS) has already been demonstrated. However, the potential prognostic role of semi-quantitative PET metabolic volume features, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), has not yet been clearly investigated. The aim of this retrospective study was to investigate whether the main metabolic PET/CT parameters may predict the prognosis. We retrospectively included 122 patients with a positive 2-[18F]FDG PET/CT for DTC disease after a negative [131I]WBS with Tg > 10 ng/mL. The maximum and mean standardized uptake value (SUVmax and SUVmean), MTV and TLG of the hypermetabolic lesion, total MTV (tMTV) and total TLG (tTLG) were measured for each scan. Progression-free survival (PFS) and overall survival (OS) curves were plotted according to the Kaplan–Meier analysis. After a median follow up of 53 months, relapse/progression of disease occurred in 87 patients and death in 42. The median PFS and OS were 19 months (range 1–132 months) and 46 months (range 1–145 months). tMTV and tTLG were the only independent prognostic factors for OS. No variables were significantly correlated with PFS. The best thresholds derived in our sample were 6.6 cm3 for MTV and 119.4 for TLG. In patients with negative WBS and Tg > 10 ng/mL, 2-[18F]FDG PET/CT metabolic volume parameters (tMTV and tTLG) may help to predict OS.

I‐PET score: Combining whole body iodine and 18F‐FDG PET/CT imaging to predict progression in structurally or biochemically incomplete thyroid cancer

“…12,15 FDG PET imaging has become increasingly important in management of patients with thyroid cancer, with FDG avid disease associated with poor prognosis. [16][17][18][19][20][21][22] FDG PET imaging have a role in detecting recurrence or persistent disease in both patients with negative WBS and elevated Tg (>10 ng/ml), and those with Tg < 10 ng/ml after initial treatment. 21,[23][24][25][26] The degree of FDG avidity has been associated with poor survival 5,17,25,27,28 and associated with poor response to RAI.…”

Positron Emission Tomography Radiopharmaceuticals in Differentiated Thyroid Cancer

“…In this clinical setting, PET/CT parameters alone or combined with other prognostic factors can help to identify patients with poor outcomes [ 39 ]. Albano et al found that the only independent prognostic factors for overall survival were total metabolic tumor volume and total lesion glycolysis of all lesions with increased [ 18 F]FDG uptake [ 40 ].…”

Application of radiomics and machine learning to thyroid diseases in nuclear medicine: a systematic review

“…Thyroid scintigraphy with 99m Tc-pertechnetate enables the functional evaluation of the gland, allowing the differentiation between thyroiditis and hyperthyroidism, but also detecting the presence of ectopic thyroid tissue [4]. Moreover, 131 I is mandatory for the management of DTC, since its pivotal role for the therapy but also the stage or the restage of the disease [5][6][7][8][9]. Beside single photon imaging, positron emission tomography (PET) has continuously spread its indication for the evaluation of DTC and associated conditions, and in the recent years many different tracers have been proposed for the assessment of such diseases [7][8][9][10][11][12].…”

“…Moreover, 131 I is mandatory for the management of DTC, since its pivotal role for the therapy but also the stage or the restage of the disease [5][6][7][8][9]. Beside single photon imaging, positron emission tomography (PET) has continuously spread its indication for the evaluation of DTC and associated conditions, and in the recent years many different tracers have been proposed for the assessment of such diseases [7][8][9][10][11][12].…”