Revolutionizing Thyroid Cancer Treatment: Restoring Radioiodine Avidity After PRRT—A Case Series

Four cases of thyroid cancer became radioiodine-refractory following conventional treatments. While no RAI-avid lesion was noticed in the initial whole-body radioiodine scan (WBIS), their metastatic foci had trace avidity. They were diagnosed as TENNIS; 2 cycles of peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTA-TATE were administrated, then the thyroglobulin levels dropped significantly. The PRRT was discontinued, and the diagnostic WBIS was repeated. Surprisingly, the scan revealed increased considerable tracer uptake in the metastatic foci. This restoration of radioiodine uptake seems to occur due to PRRT-induced tumor irradiation. Suggesting PRRT may serve as a potential re-differentiation strategy in TENNIS.