Outcomes of children and adolescents with well-differentiated thyroid carcinoma and pulmonary metastases following ¹³¹I treatment: A systematic review

Background: The optimal dose and efficacy of ¹³¹I treatment of children and adolescents with well-differentiated thyroid carcinoma (WDTC) and pulmonary metastases are not well established. A therapeutic challenge is to achieve the maximum benefit of ¹³¹I to decrease disease-related morbidity and obtain disease-free survival while avoiding the potential complications of ¹³¹I therapy. Summary: We systematically reviewed the published literature on children and adolescents with WDTC and pulmonary metastases treated with ¹³¹I to examine outcomes after ¹³¹I administration and the risks and benefits of therapy. After reviewing 14 published articles, 9 articles met our inclusion criteria encompassing 112 pediatric and adolescent patients with WDTC and pulmonary metastases 21 years of age or younger at diagnosis spanning a follow-up period of 0.6-45 years. ¹³¹I therapy after surgery and thyrotropin suppression resulted in complete, partial, and no disease response in 47.32%, 38.39%, and 14.29% of patients, respectively. Five studies provided data on disease response in relation to ¹³¹I dose. In general, nonresponders received the highest ¹³¹I doses and complete responders received a higher dose than partial responders. The disease-specific mortality rate was 2.68%. Survival was 97.32%. A second primary malignancy occurred in one patient. One out of 11 patients studied experienced radiation fibrosis. Conclusions: This review confirms that the majority of pediatric and adolescent patients with WDTC and pulmonary metastases treated with ¹³¹I do not achieve complete response to therapy, yet disease-specific morbidity and mortality appear to remain low. It is therefore prudent to use caution in the repeated administration of ¹³¹I to such patients to ensure that adverse effects of therapy do not cause more harm than good in a disease that has an overall favorable natural course. Long-term prospective studies are needed to analyze disease-specific morbidity and mortality, recurrence rate, dose-specific response, and dose-related adverse effects of ¹³¹I in this patient population.