Can 99Tcm-3PRGD2(ανβ3) and 18F-FDG dual-tracer molecular imaging change the therapeutic strategy for progressive refractory differentiated thyroid cancer: Case report.

Abstract

The management of radioiodine refractory differentiated thyroid cancer (RAIR-DTC) represents a major challenge in thyroid cancer. The American Thyroid Association guidelines recommend the use of tyrosine kinase inhibitors (TKIs) for RAIR-DTC that does not respond to conventional treatment. Currently, imaging modalities that predict the response to TKI treatment based on morphological and functional features are lacking. we report a case of a patient with progressive RAIR lung metastases who underwent 2-deoxy-2-[18F]fluoro-D-glucose and 99technetiumm-three polyethylene glycol spacers-arginine-glycine-aspartic acid (99Tcm-3PRGD2) dual-tracer imaging and investigate the value of this imaging strategy for determining subsequent therapeutic schedules. A 52-year-old man with advanced RAIR-DTC and progressive lung metastasis. After TKI treatment [sorafenib] lost its clinical benefits, the patient's therapeutic response was evaluated as progressive disease. 2-deoxy-2-[18F]fluoro-D-glucose PET/CT and 99Tcm-3PRGD2 SPECT/CT were performed. There were multiple FDG-positive lesions in the lung. However, 99Tcm-3PRGD2 SPECT/CT showed only 1 lesion in the right middle pulmonary lobe with arginine-glycine-aspartic positivity. RAIR-DTC. Radiofrequency ablation was performed for only the lesion with RDG and FDG positivity. The patient quickly achieved partial response. This case indicates that for progressive RAIR metastases, patients can benefit more from prioritizing treatment for lesions that are both arginine-glycine-aspartic and FDG positive.