Albano D, Tulchinsky M, Dondi F, Mazzoletti A, Bertagna F, Giubbini R. The role of Tg kinetics in predicting 2-[
18F]-FDG PET/CT results and overall survival in patients affected by differentiated thyroid carcinoma with detectable Tg and negative 131I-scan.
Endocrine 2021;
74:332-339. [PMID:
34014437 PMCID:
PMC8497300 DOI:
10.1007/s12020-021-02755-5]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 05/05/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE
The aim of this study was to assess the potential role of thyroglobulin (Tg) kinetics in predicting 2-[18F]-FDG-PET/CT results and overall survival (OS) in patients affected by differentiated thyroid carcinoma (DTC) and suspected recurrence.
METHODS
On hundred and thirty-nine patients were retrospectively included. All patients underwent 2-[18F]-FDG-PET/CT due to detectable Tg levels and negative [131I] whole-body scan. The last two consecutive serum Tg measurements before PET/CT were used for Tg-doubling time (TgDT) and Tg-velocity (Tg-vel) calculation. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff points for Tg, TgDT and Tg-vel for predicting PET/CT results.
RESULTS
One hundred and fifteen (83%) patients had positive PET/CT for DTC recurrence, while the remaining 24 (17%) negative. Stimulated Tg before PET and Tg-vel were significantly higher in patients with a positive PET/CT scan than negative scan (average Tg 190 vs 14 ng/mL, p = 0.006; average Tg-vel 4.2 vs 1.7 ng/mL/y, p < 0.001). Instead, TgDT was significantly shorter in positive scan (average TgDT 1.4 vs 4.4 years, p < 0.001). ROC curve analysis revealed the best Tg, TgDT and Tg-vel cutoff of 18 ng/mL,1.36 years and 1.95 ng/mL/y. In patients with Tg<18 ng/mL, the PET/CT detection rate was significantly lower in patients with low Tg-vel (p = 0.018) and with long TgDT (p = 0.001). ATA class risk, PET/CT results and Tg before PET were confirmed to be independent prognostic variables for OS.
CONCLUSIONS
Tg kinetics may help to predict 2-[18F]-FDG-PET/CT results in DTC patients with negative [131I]WBS and detectable Tg, especially in case of low-moderate Tg.
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