TERT promoter mutations contribute to adverse clinical outcomes and poor prognosis in radioiodine refractory differentiated thyroid cancer.

Telomerase reverse transcriptase promoter (TERTp) mutations are associated with non-radioiodine avidity. However, the role of these mutations in the clinical outcomes of patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC) remains unknown. Herein, we aim to analyze gene mutations and clinical manifestations to verify TERTp's role in driving disease progression to RAIR-DTC and clinical outcomes. Next-generation sequencing data and clinical data were obtained from 243 patients with DTC. Of the 25 patients with TERTp mutations, 80% (20/25) had RAIR-DTC. RAIR-DTC was significantly less prevalent in patients with BRAF (9/143, 6.3%) than those with both BRAF and TERTp mutations (14/17, 82.4%). Patients with RAIR-DTC harboring both BRAF and TERTp mutations were more likely to have > 3 distant metastatic sites (85.7%, 12/14) than those with BRAF alone (33.3%, 3/9). Only one patient with both BRAF and TERTp mutations had non-RAIR-DTC. The time from initial radioactive iodine therapy to RAIR-DTC diagnosis was significantly shorter in patients with TERTp mutations than in those without. Patients with BRAF and TERTp mutations progressed faster to RAIR-DTC than those with BRAF alone (p < 0.01). Our findings suggest that molecular testing for TERTp and other mutations like BRAF may inform early diagnosis, prognosis, and treatment strategies before progression to RAIR-DTC.