Comparing therapeutic outcomes: radioactive iodine therapy versus non-radioactive iodine therapy in differentiated thyroid cancer.

Introduction: Radioactive iodine (RAI) has been utilized for nearly 80 years in treating both hyperthyroidism and thyroid cancer, and it continues to play a central role in the management of differentiated thyroid cancer (DTC) today. Recently, the use of RAI therapy for indolent, low-risk DTC has generated considerable debate. This case-control study evaluated the therapeutic response in DTC patients, comparing outcomes between those who received RAI therapy and those who did not. Methods: The study included individuals diagnosed with either indolent or aggressive histological types of DTC who either underwent RAI therapy or did not. For each patient, information regarding demographics (age, sex, background), clinical data, laboratory parameters, pathological exam, history of RAI therapy, thyroid ultrasound findings, and loco-regional or distant metastasis was extracted. All group comparisons were made using a two-sided test at an α level of 5%. Results: Out of 104 patients diagnosed with DTC, 76 met the inclusion criteria and were subsequently divided into two primary groups based on their history of RAI ablation. The majority of patients underwent RAI therapy (76.3%). Most patients had a good biochemical (68.4%, p = 0.246) and structural control (72.4%, p = 0.366), without a significant difference between the two groups. RAI therapy significantly protected against incomplete biochemical control in the overall population (p = 0.019) and in patients with histological indolent DTC (p = 0.030). Predictive factors for incomplete biochemical control included male sex (p = 0.008) and incomplete structural control (p = 0.002) across all patients, regardless of the histological type. Discussions: While RAI therapy has traditionally been used to manage DTC, our study found no significant difference in biochemical and structural responses between patients who received RAI therapy and those who did not. However, RAI therapy emerged as a protective factor against incomplete biochemical control, even in histological indolent DTC cases. These findings suggest that while RAI therapy may not be universally necessary, it could be beneficial in reducing the risk of biochemical recurrence in select patient subgroups, such as those with incomplete structural control or male patients. Thus, a personalized approach to RAI therapy, tailored to individual risk factors, may improve patient outcomes without overtreatment.