Risk of second primary malignancies after radioactive iodine treatment for pediatric and young adulthood DTC

Since the 1980s, both the incidence of differentiated thyroid cancer (DTC) and use of radioactive iodine (RAI) treatment for DTC increased markedly. RAI has been associated with an increased risk of leukemia, but risks of second solid malignancies remain unclear. Analysis of nine SEER cancer registries found that RAI treatment for pediatric and young adulthood DTC was associated with increased risks of second primary solid malignancies (A) and hematologic malignancies including leukemia (B). The risk of total solid cancer and female breast cancer, the most common solid cancer type, were particularly elevated after more than 20 years of follow-up.