FAP-Targeted Radionuclide Therapy of Advanced Radioiodine-Refractory Differentiated Thyroid Cancer With Multiple Cycles of 177Lu-FAPI-46

Abstract Many recent studies began to explore the therapeutic potential of FAP-targeted radionuclide therapy for refractory cancers. In this case, we presented the experience of multiple cycles of 177 Lu-FAPI-46 radionuclide therapy in a 34-year-old man with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). Intense radiotracer uptake was observed in RAIR-DTC metastatic lesions on the pretreatment 68 Ga-FAPI PET/CT and posttherapeutic scintigraphy. Follow-up examinations after 4 cycles of 177 Lu-FAPI-46 treatment revealed stable metastatic lesions, resulting in stable disease. This case demonstrated the potential feasibility of 177 Lu-FAPI-46 in the treatment of advanced RAIR-DTC; further research on improving the FAP-targeting vector may be necessary.