ODP463 Assess the Usefulness of Pre–Ablation Diagnostic I-123 Iodine Scans in Patients with Differentiated Thyroid Cancer

Abstract

Abstract Context: Over the last decade, there have been significant changes in the post-operative management of Differentiated Thyroid cancer. The use of Diagnostic 123-Iodine scans has become controversial as many endocrinology practices now give empiric doses of RAI (Radioactive Iodine) when needed based on risk stratification. Allegheny Health Network (AHN) routinely uses I-123 Pre RAI scans prior to ablative or adjuvant therapy. As per the 2015 ATA (American Thyroid Association) guidelines – Pre therapy scans and/or measurement of thyroid bed uptake may be useful when the extent of the thyroid remnant cannot be accurately ascertained from the surgical report or neck ultrasonography, or when the results would alter either the decision to treat or alter the activity of RAI dose that is administered. ATA recommendation is vague and further studies are needed to identify these patients who need pretreatment scan. Objective The objective of our study is to evaluate the utility of pre-therapy diagnostic 131-I scan for the risk stratification and Radioactive Iodine administration decisions in patients with Differential Thyroid cancer after thyroidectomy. Design: The study is a retrospective blinded chart review of cases at AHN. Setting: The study was conducted at an academic tertiary care center of a large Health Network in Western Pennsylvania. Method: Retrospective chart review of patients at AHN who underwent RAI treatment from 2016-2021 has been completed. 195 patients with Differentiated Thyroid cancer have been included in this study. These patients had a pre-therapy WBI (Whole Body Iodine) scan as per AHN's current clinical practice. Data collection includes demographic information, surgical details including lymph neck dissection performed or not, tumor histopathology, TNM classification, post thyroidectomy labs including TSH (Thyroid Stimulating Hormone), TG (Thyroglobulin) and TGA (Thyroglobulin antibody), pre and post-operative ultrasound, RAI dose, Pre-therapy scan findings and Post therapy RAI scan findings. Intervention: Using clinical and histopathology information a group of blinded endocrinologist are performing risk stratification to determine postoperative management with respect to radioiodine therapy (RAI) planning. The decision to withhold or to administer RAI, and the recommended low, medium or high 123-I activity will be decided by them without having information from the Diagnostic 123-Iodine scans. Main Outcome Measure: Main outcome measures will be difference in risk stratification and management with and without Diagnostic 123-Iodine scans. We plan to compare this empiric management strategy to the actual management strategy that took place based on the Pre-therapy scan. Results This will include percentage of patients where decision to treat or dose of radioactive iodine was different, when information from Diagnostic 123-Iodine scan was not available. This will help streamline Endocrinologist practice for patients with Differentiated Thyroid cancer. Presentation: No date and time listed