A retrospective cohort study by investigators at Children's Hospital of Philadelphia (CHOP) of patients under the age of 19 with low-risk differentiated thyroid cancer (DTC) who had undergone a total thyroidectomy at CHOP between 2010 and 2020 showed that those who are spared radioactive iodine (RAI) therapy show no decrease in the rate of remission compared with those who receive it.
Prior to 2015, the standard treatment for DTC in pediatric patients was thyroidectomy followed by RAI. However, with concerns for acute and long-term toxicity from RAI, including salivary gland dysfunction (acute) and a low but increased risk for secondary malignancies, efforts were undertaken to identify which patients may achieve remission without RAI. As a result, the 2015 American Thyroid Association pediatric guidelines recommended that pediatric patients should not get RAI when the cancer is mostly confined to the thyroid (ATA pediatric low-risk).
“This is the first study to validate those guidelines,” says first author Mya Bojarsky, a 2022 student scholar in the CHOP Research Institute Summer Scholars Program. The findings were presented at the American Thyroid Association 2022 Annual Meeting in Montreal. “Withholding RAI therapy is clinically beneficial as it reduces exposure to radiation while having no negative impact on remission."
Senior author Andrew J. Bauer, MD, Director of the Pediatric Thyroid Center at CHOP, added that the study also shows that one year post-thyroidectomy is an early but accurate time point for initial assessment of remission in low-risk patients. He also noted that the approach of withholding RAI had been recently validated through a prospective study in adults with low-risk DTC.
The CHOP study included 95 ATA low-risk patients treated with thyroidectomy, 50 of whom had been treated with RAI and 45 who did not receive RAI. At one year post-thyroidectomy, the remission rate for those who received RAI was 80%, and for those who did not receive RAI the remission rate was 84%, with increasing rates of remission, up to 90% and 87%, respectively, with continued surveillance.