Management of radioiodine ablation therapy in haemodialysis patients with thyroid cancer: a case series of two patients

Abstract Background Radioiodine (¹³¹I) therapy in treatment of thyroid cancer, has a biological clearance that is significantly reduced in end-stage kidney disease (ESKD), leading to increased radiation exposure and potential myelotoxicity. For ESKD patients on haemodialysis (HD), there is no standardized approach to ¹³¹I administration and scheduling of HD following. Methods Two patients with ESKD on HD were treated with ¹³¹I therapy for thyroid cancer. Local ¹³¹I treatment protocol was modified to account for ESKD and HD. Modifications were made to existing infrastructure and additional patient and staff safety precautions were undertaken, including serum ¹³¹I measurements to monitor for myelotoxicity. Results HD at 24-,72- and 144-hours post-¹³¹I results in a retained radiation activity profile comparable to patients with normal renal function. Radiation dose to bone marrow throughout treatment was assessed at < 0.3 Gy for both patients. The highest contribution of radiation dose to bone marrow (60% and 47% for patient 1 and patient 2 respectively) was due to the radioactivity retained in blood before the first HD session. Cumulative radiation exposure to dialysis staff during therapy was well within local safety constraints. At 18 months post-therapy, remnant thyroid ablation was successful in both patients. Conclusions ¹³¹I therapy can be safely administered in patients with ESKD on HD with modifications to existing infrastructure and protocols. Serum ¹³¹I measurements is a simple and minimally invasive method to assess bone marrow safety during treatment. Ongoing pooling of experiences is needed to inform a standardized protocol for therapy in this population.