FDG PET/CT in differentiated thyroid cancer patients with low thyroglobulin levels. Issue 1 (24th May 2022)

• Record Type: Journal Article
• Authors: Lebbink, Chantal A; de Vries, Lisa H; Borel Rinkes, Inne H M; Braat, Arthur J A T; van Leeuwaarde, Rachel S; Lodewijk, Lutske; van Treijen, Mark J C; Vriens, Menno R; Valk, Gerlof D; van Santen, Hanneke M; de Keizer, Bart
• Is Part Of: European journal of endocrinology. Volume 187:Issue 1(2022)
• Page Start: 101
• Page End: 110
• Publication Date: 2022-05-24
• Subjects: Endocrinology -- Periodicals; 616.4005
• DOI: 10.1530/EJE-22-0072
• Languages: English
• ISSNs: 0804-4643

Abstract

Abstract: Objective: To evaluate the usefulness of [ 18 F]fluorodeoxyglucose (FDG) positron emissive tomography (PET)/CT in patients with low detectable thyroglobulin levels suspicious for persistent or recurrent differentiated thyroid cancer (DTC). Methods: A retrospective case series study evaluating FDG PET/CT in patients with detectable thyroglobulin (Tg) levels (≥0.20 and <10.00 ng/mL) after initial treatment with total thyroidectomy and I-131 thyroid remnant ablation for pT1-3aN0-1bM0 DTC. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of FDG PET/CT were calculated. Results: Twenty-seven patients underwent FDG PET/CT. Median Tg level at FDG PET/CT was 2.00 ng/mL (range 0.30–9.00). FDG PET/CT was positive in 14 patients (51.9%): lesions suspicious for lymph node metastases were depicted in 12 patients, and lung metastases in 2. DTC was confirmed in 13/14 FDG PET/CT-positive patients. In 9/13 patients with a negative FDG PET/CT, DTC was confirmed ≤3 months after FDG PET/CT. The sensitivity, PPV, specificity and NPV were 59.1, 92.9, 80.0 and 30.8%, respectively. Conclusions: This case series shows that FDG PET/CT might be useful to detect persistent or recurrent DTC in patients with low detectable Tg. However, when FDG PET/CT is negative, this does not rule out DTC and further investigations are necessary.