MON-339 Balancing Act: Radioactive Iodine Treatment for Papillary Thyroid Cancer in a Patient With End Stage Renal Disease

Abstract Disclosure: J.E. Marquez: None. H.R. Go: None. M.A. Co: None. BackgroundWhile the treatment of Papillary Thyroid Cancer (PTC) by total thyroidectomy and some followed by radioactiveiodine (RAI) therapy is straightforward, use of RAI may pose a challenge in handling patients with coexisting End-Stage Renal disease (ESRD). Management challenges in treating PTC in a patient with ESRD may include the determination of ideal dosage of radioactive iodine and timing of hemodialysis to maximize its therapeutic effect while minimizing its radioactive side effects.Clinical CaseWe present a 44-year-old Filipino male with ESRD and tertiary hyperparathyroidism post total thyroidectomy with parathyroidectomy. Histopathology of the resected thyroid revealed multifocal PTC, a classical type on the right superior pole (1.2 cm) and infiltrative follicular variant on the left lobe (0.5 cm). There was no invasion of the lymphovascular space and extension beyond the thyroid, AJCC stage I (T1bN0M0). Radioactive iodine (RAI) ablation is not routinely recommended after total thyroidectomy for patients with ATA low risk DTC. However, specific clinical features such as multifocality (∼4-6%) made us decide to give radioactive iodine treatment to our patient. With collaborative discussion involving nephrology and nuclear medicine service, RAI dose 40 mCi was administered a month after surgery, radiation precautions were observed and discharged after 2 days with radiation activity <2mR/hr. Hemodialysis post RAI treatment was scheduled 48 hours post therapy. Differentiated Thyroid Cancer not only has higher incidence in Filipinos but also has higher disease recurrence and mortality rate compared with other ethnicities which warrants more aggressive management. End Stage Renal Disease prolongs the excretion of I131 which affects the radiation dose exposure to the body causing higher side effects particularly on the bone marrow. In dialysis patients, dosing recommendations were contradictory and the timing of hemodialysis is crucial. Existing literatures mostly suggest lowering 13-30% from the therapeutic dose. Dialysis is carefully planned to do hemodialysis pretreatment closest to administration of RAI and waiting 48 hours for the next treatment post-RAI treatment. Still, there is no specific recommendations in the use of RAI in patients with ESRD. ConclusionThis work reports our first experience in the use of RAI for managing thyroid cancer in a patient with ESRD undergoing hemodialysis. Only limited data, particularly in our local setting, is available given the rarity of thyroid cancer in hemodialysis patients. Multidisciplinary team approach involving specialists in nuclear medicine, endocrinology, and nephrology is of utmost importance in handling these subset of patients to facilitate the therapeutic benefits and safe use of RAI treatment. Presentation: Monday, July 14, 2025