Radioactive iodine therapy may not improve disease-specific survival in follicular variant papillary thyroid cancer without distant metastasis: A propensity score-matched analysis

Background Whether radioactive iodine (RAI) therapy is effective in improving disease-specific survival (DSS) in patients with follicular variant papillary thyroid cancer (FVPTC) without distant metastasis remains unclear. Methods Patients with FVPTC were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015. The Kaplan-Meier method and the Cox proportional hazards regression model were used to evaluate DSS. Propensity score-matched analysis was performed to reduce the influence of confounding bias. Results RAI did not improve DSS, even in patients with aggressive features such as T4 classification (p = 0.658), extrathyroidal extension (p = 0.083), lateral lymph node metastasis (p = 0.544), and >= 5 metastatic lymph nodes (p = 0.599). Conclusion RAI did not affect DSS in patients with FVPTC without distant metastases in this SEER database study. Multicenter, prospective studies including recurrence and molecular information should be conducted to comprehensively evaluate the effects of RAI on FVPTC.