Radioiodine Remnant Ablation for Differentiated Thyroid Cancer

Abstract

IMPORTANCEPostoperative radioactive iodine (RAI) remnant ablation for differentiated thyroid cancer (DTC) facilitates the early detection of recurrence and represents an adjuvant therapy that targets persistent microscopic disease. The optimal activity of RAI in low-and intermediate-risk DTC remains controversial. OBJECTIVE To evaluate the long-term cure rate of different RAI activities in low-and intermediate-risk DTC. Secondary outcomes included successful remnant ablation, adverse effects, and hospital length of stay. DATA SOURCE A systematic search of the databases PubMed, Cochrane Collaboration, Embase, Scopus, and Web of Science was performed to identify randomized clinical trials (RCTs) and observational studies that compared long-term outcomes (>12 months) for American Thyroid Association-classified low-and intermediate-risk DTC based on receipt of either low-activity or high-activity RAI postoperatively.STUDY SELECTION All RCTs or observational studies evaluating patients with low-and intermediate-risk DTC who were treated initially with total/near-total thyroidectomy, followed by remnant RAI ablation with either low or high activities. Eligible studies had to present odds ratio, relative risk (RR), or hazard ratio estimates (with 95% CIs), standard errors, or the number of events necessary to calculate these for the outcome of interest rate.DATA EXTRACTION Two investigators reviewed the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Dichotomous variables were pooled as risk ratios and continuous data as weighted-mean differences. Quality assessment of the included studies was performed using the Newcastle-Ottawa and Jadad scales.MAIN OUTCOMES AND MEASURES Disease recurrence was the primary outcome. Secondary outcomes included successful ablation, adverse effects, and length of stay. RESULTSTen studies that included 3821 patients met inclusion criteria, including 6 RCTs and 4 observational studies. There was no difference in long-term cure recurrence rates (RR, 0.88; 95% CI, 0.62-1.27, P = .50) or successful remnant ablation (RR, 0.95; 95% CI, 0.87-1.03; P = .20) between low-activity and high-activity RAI. CONCLUSIONS AND RELEVANCEIn this systematic review and meta-analysis, low-activity RAI was comparable with high-activity RAI regarding successful ablation and recurrence rates. This suggests that low-activity RAI is preferable to high-activity in low-and intermediate-risk DTC because of its similar efficacy but reduced morbidity.

Association Between Radioactive Iodine Treatment for Pediatric and Young Adulthood Differentiated Thyroid Cancer and Risk of Second Primary Malignancies

“…3 Use of radioactive iodine (RAI) for DTC treatment also increased through 2009, especially in young patients. [4][5][6][7][8][9] However, in addition to providing limited to no survival benefit for localized DTC, RAI is associated with increased risks of short-term and long-term adverse outcomes, [10][11][12][13][14] including secondary primary malignancies (SPMs), such as leukemia. [15][16][17][18][19][20][21][22] In response to this evidence, the 2009 and 2015 American Thyroid Association guidelines committee issued recommendations against RAI therapy for low-risk DTCs , 1 cm and in support of lower levels of RAI administered activity for larger tumors.…”

Strategies for Radioiodine Treatment: What’s New

“…On the whole, the ESTIMABL1 [ 8 ] and HiLo [ 9 ] trials independently support the use of 1.1 GBq of radioiodine under rhTSH stimulation for RRA in low-, but also intermediate-risk DTC. The equivalence of low radioiodine activity for RRA was also confirmed by several meta-analyses [ 29 , 30 ].…”

Correlation analysis of I-131 SPECT/CT uptake parameters with the success ablation treatment of thyroid remnant in patients with low-intermediate-risk differentiated thyroid cancer

“…The low uptake of the thyroid after RAI may be related to the degree of surgical resection, which leads to great differences in the weight of thyroid remnants. The less thyroid remnant, the better the effect of I-131 ablation success, including reducing DTC recurrence, adverse side effects and duration of hospitalization [19]. The patients included in this study were total thyroidectomy.…”