Supplementary Material for: Response of Retinoic Acid in Patients with Radioactive Iodine-Refractory Thyroid Cancer: A Meta-Analysis

<p><b><i>Purpose</i></b>: The purpose of this study was to evaluate the response of retinoic acid (RA) in radioactive iodine (RAI)-refractory differentiated thyroid cancer (DTC). <b><i>Methods:</i></b> Systematic searches of MEDLINE (from inception to December 2016) and of EMBASE (from inception to December 2016) were performed for English-language publications on thyroid cancer treated with RA. Studies were classified according to the response criteria used: (1) <sup>123</sup>I or <sup>131</sup>I whole body scintigraphy (WBS), (2) serum thyroglobulin (Tg) level, (3) the response evaluation criteria in solid tumors (RECIST) version 1.0, and (4) World Health Organization (WHO) criteria. <b><i>Results:</i></b> Disease response rates as determined by WBS ranged widely between 6.2% and 46.1% with a pooled disease response rate of 27.6% (95% confidence interval: 21.7-34.0%). Response rates as determined by Tg level ranged from 56.6% to 83.3% (pooled response rate 61.3% (51.0-70.9%)), RECIST response rates from 0% to 45.5% (pooled response rate 17.0% (1.4-44.5%)), and according to WHO criteria, the pooled response rate was 30.8% (12.7-52.7%). <b><i>Conclusions:</i></b> A minority of patients with RAI-refractory DTC respond to RA treatment.</p>