ASTRO 2020: High-Dose Iodine-131 Ablation for High-Risk Thyroid Cancer
Posted: Monday, November 16, 2020
Even patients with differentiated thyroid carcinoma who have adverse high-risk pathologic features may be successfully treated after surgery with adjuvant high-dose iodine-131 ablation, results of a retrospective analysis indicate. Furthermore, two preparation techniques for ablation—thyroid hormone withdrawal and thyrotropin-alpha—seemed to work equivalently well. Robert S. Kwon, MD, of the University of California Los Angeles, and colleagues discovered.
The investigators found that of 142 patients with stage I to IV papillary and follicular thyroid carcinomas, 119 (84%) achieved complete ablation after one treatment of high-dose iodine-131, and another 18 (13%) achieved it after two treatments. They reported their results during the virtual edition of the 2020 Annual Meeting of the American Society for Radiation Oncology (ASTRO; Abstract 3937).
“There was no significant difference in the use of either preparation technique, thyroid hormone withdrawal vs. thyrotropin-alpha (P = .87) independent of the number of ablative treatments,” reported Dr. Lee and his team. In terms of the iodine, patients receiving one and two treatments had, on average, doses of 135 mCi and 293 mCi, respectively. Five patients (3%) received three treatments but did not meet complete ablation criteria nonetheless. In such cases, other novel systemic therapies might be attempted, the researchers stated.
The patient cohort had a variety of pathologic features that made their disease high risk. These features included primary tumor size > 4 cm, macroscopically multifocal disease, extrathyroidal extension, high-risk histologic variants, lymphovascular invasion, regional nodal metastases, and positive surgical margins.
Disclosure: The study authors reported no conflicts of interest.