Simões-Pereira J, Mourinho N, Ferreira TC, et al. - In this retrospective analysis, researchers analyzed all differentiated thyroid cancer (DTC) patients submitted to radioiodine therapy (RAIT) because of distant metastatic disease, between 2001-2018, to determine the connection between histology and RAIT avidity and response; to assess if histotype represented an independent prognostic factor in progression-free survival (PFS) and disease-specific survival (DSS) post-RAIT for distant metastatic disease. This analysis involved 126 patients. RAIT avidity was identified to be independently related to histology and stimulated thyroglobulin at first RAIT for distant lesions. Concerning RAIT response, no difference was evident between HCC and follicular thyroid cancer; both demonstrated significantly more often progression post- RAIT vs follicular variant papillary thyroid cancer and classical variant papillary thyroid cancer. Factors that were significantly related to DSS included: age at diagnosis, resection status, and stimulated thyroglobulin at the first RAIT. Findings demonstrated an impact of DTC histotype on RAIT avidity as well as on PFS. It is essential to better identify the metastatic cases that may benefit the most from RAIT.