The Effectiveness of Radioactive Iodine Remnant Ablation for Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis

Background This systematic review and meta-analysis aimed to evaluate the effectiveness of radioactive iodine (RAI) remnant ablation for thyroid cancer-related outcomes of patients with papillary thyroid microcarcinoma (PTMC). Methods A systematic literature search of PubMed, EMBASE OvidSP, and EBSCO was conducted. Studies were selected that provided multivariable analysis of the effectiveness of RAI ablation or provided specific data of a 10 years history of thyroid cancer-related outcomes in patients that presented with PTMC. Results Nineteen studies met the inclusion criteria. A multivariable analysis of the effectiveness of RAI ablation for any recurrence or thyroid cancer-related mortality in patients with PTMC was performed in several studies, among which only one study reported a positive result. Furthermore, for PTMC patients treated by total or near-total thyroidectomy (TT/NT), with or without RAI ablative therapy, the meta-analysis suggested that RAI ablation did not decrease the 10 years history of any tumor recurrence (relative risk [RR] 0.96; 95 % confidence interval [CI] 0.63–1.48; P = 0.87), locoregional recurrence (RR 1.15; 95 % CI 0.75–1.76; P = 0.51), distant metastases (RR 0.32; 95 % CI 0.08–1.32; P = 0.11) or thyroid cancer-related mortality (RR 0.76; 95 % CI 0.22–2.63; P = 0.66). Conclusions With regard to multivariable analyses, there was almost no positive treatment effect of RAI ablation noted for patients with PTMC. For PTMC patients already treated by TT/NT, incremental RAI ablation may not be beneficial at decreasing the 10 years recurrence of PTMC or incidence of thyroid cancer-related mortality.