Beyond the Burn: Leukemia Threats Following Radioactive Iodine Ablation Therapy for Thyroid Cancer

<b>Background:</b> Radioactive iodine (RAI) ablation therapy is a common minimally invasive treatment for patients diagnosed with differentiated thyroid cancer (DTC). Although previous studies have identified a link between RAI and the mortality from secondary solid cancers, the connection between RAI and leukemia remains under-researched. This study investigated the differential risk of leukemia and its subtypes in DTC patients following RAI treatment. <b>Methods:</b> DTC patients from the Surveillance, Epidemiology, and End Results (SEER) Registry 17 (2000-2019) were analyzed. The standard incidence ratio (SIR) and excess risk (ER) compared to the reference population were calculated. <b>Results:</b> Out of 196,569 DTC patients, 1381 patients developed various types of hematological malignancies. Leukemia was diagnosed in 508 of these patients, and it had the highest risk among the malignancies studied, with an SIR of 1.74 (95%CI: 1.59-1.9). The RAI group had an SIR of 2.12 (95%CI: 1.87-2.39), while the non-RAI group had an SIR was 1.45 (95%CI: 1.37-1.52) (<i>p</i> < 0.001). Those diagnosed before the age of 55 years had a conspicuously elevated risk (SIR 2.74) compared to those diagnosed at 55 years or older (SIR 1.53). American Indian/Alaska Native survivors manifested a pronounced leukemia risk with an SIR of 7.63 (95%CI: 2.46-17.8). <b>Conclusions:</b> RAI treatment increased the risk of developing leukemia when serving as adjuvant therapy in surgical patients (SIR 2.12). There exists a significant association between RAI treatment in DTC patients and the incidence of leukemia. This susceptibility seems to be modulated by factors including time since diagnosis, age, gender, and racial background.