Evaluation of the usefulness of positron emission tomography with [18F]fluorodeoxylglucose performed to detect non-radioiodine avid recurrence and/or metastasis of differentiated thyroid cancer — a preliminary study

Abstract

Background: About 30% of patients with disseminated differentiated thyroid cancer (DTC) may experience a loss of iodine uptake. It is associated with higher aggressiveness of the tumour and a reduced 10-year survival rate. The diagnosis of non-radioiodine avid DTC metastases remains a diagnostic challenge. A helpful technique for this diagnosis is positron emission tomography with 2-[ 18 F]fluoro-2-deoxy-D-glucose (PET/CT with [ 18 F]FDG). On the other hand, there are still discussions about the clinical value of using exogenous thyroid-stimulating hormone (TSH) stimulation before PET/CT with [ 18 F]FDG.The aim of the study was the assessment of the usefulness of PET/CT with [ 18 F]FDG under TSH suppression and stimulation of TSH performed in the detection of non-radioiodine avid DTC metastases, as well as determination of the thyroglobulin concentration under suppression and stimulation of TSH, which influences the result of PET/CT with [ 18 F]FDG in patients with non-radioiodine avid DTC. Material and methods:Retrospective analysis of 37 PET/CT with [ 18 F]FDG performed in patients with DTC diagnosed and treated at the Department of Endocrinology and Isotope Therapy of the Military Institute of Medicine from January 2018 to July 2020. Of these, PET/CT with [ 18 F]FDG under exogenous rhTSH stimulation was performed in 22 patients and PET/CT with [ 18 F]FDG under TSH suppression in 15 was performed. In all analyzed patients, the result of diagnostic whole-body scintigraphy (WBS) using 80 MBq 131 I under rhTSH stimulation was negative, and the concentration of thyroglobulin after stimulation (sTg) was greater than 1.0 ng/mL.

PET-CT in Clinical Adult Oncology—V. Head and Neck and Neuro Oncology

“…FDG PET-CT is also important in evaluating for retropharyngeal nodal involvement, which is often clinically silent and difficult to recognize by other imaging modalities. There is some evidence that the sensitivity of FDG PET-CT for DTC is greater if the thyroid stimulating hormone (TSH) is elevated at the time of imaging, although the evidence to support the value of exogenous human recombinant TSH (rhTSH) in PET-CT for DTC is contradictory [ 83 ]. In patients with high-risk differentiated thyroid cancer, there is some support for the application of FDG PET-CT as an initial staging procedure [ 84 ].…”

PET-CT en el carcinoma anaplásico de tiroides y otros subtipos histológicos agresivos

“…El PET-CT con 18 F-FDG es una herramienta útil para la detección de metástasis o recurrencia del CDT no ávido por el radioyodo [27], alcanzando una sensibilidad del 79.4% y una especificidad del 79.4% [28].…”