177Lu-FAPI-2286 Therapy in a Patient With Radio-iodine Refractory Papillary Thyroid Carcinoma: A Favorable Clinical and Biochemical Response.

We report a 38-year-old man with radio-iodine refractory papillary thyroid carcinoma (RAIR PTC) who experienced significant relief from symptoms and showed a positive biochemical response after undergoing a single cycle of 177Lu-FAPI-2286 therapy. A pretreatment 99mTc-FAPI-46 scan showed diffuse uptake throughout both lungs and subsequent serial post-treatment scans demonstrated sustained uptake in pulmonary metastases. After treatment, there was a significant decline in serum thyroglobulin levels, accompanied by a remarkable improvement in symptoms, leading to near-complete resolution. This case highlights the potential of 177Lu-FAPI-2286 therapy as an effective treatment option for RAIR PTC patients.