No reinduction of clinically relevant radioiodine uptake after lenvatinib treatment in radioidine-refractory differentiated thyroid cancer

Author(s):
Dotinga, M. (0000-0002-8384-7164); Geus-Oei, L.F. de; Velden, F.H.P. van (0000-0003-2859-2119); Stam, M.K.; Heemskerk, J.W.T.; Dibbets-Schneider, P.; Pool, M.; Smit, F.; Vriens, D. (0000-0001-5762-6766); Kapiteijn, E.
Published
2025
Publication type
Article / Letter to editor

Abstract

Nine RAI-R DTC patients starting lenvatinib treatment for progressive advanced or metastatic disease, were included and underwent rhTSH-stimulated I-124 dosimetric procedures at baseline, week 6 (N=7) and week 12 (N=8). At all timepoints, the fraction of patients eligible for I-131 therapy with a maximal activity of 7.4 GBq was assessed. Patients were considered eligible if at least one target lesion showed an expected mean absorbed dose >= 20 Gy. In total, 23 target lesions were segmented on(124)I PET/CT images and their volumes estimated using low-dose CT images. Lesion size-specific recovery correction was applied to the measured mean activity concentration at each timepoint. Tumor dosimetry was performed using a mono-exponential fit and S-values from an internal dosimetry program for diagnostic nuclear medicine based on the ICRP adult reference voxel phantoms (IDAC-Dose2.1). Mean absorbed lesion dose per administered activity (LDpA), 24h-uptake and residence time in target lesions were compared between time points.

LenvatinibRedifferentiationRadioiodine refractoryThyroid cancerI-124Dosimetry
Date issued
2025-12-16
Language
English
Publisher
SPRINGER
Is part of
European Journal of Nuclear Medicine and Molecular Imaging
hdl
1887/4293395
doi
10.1007/s00259-025-07662-9