Changes in Population-Level and Institutional-Level Prescribing Habits of Radioiodine Therapy for Papillary Thyroid Cancer.

Background: In the past two decades, new evidence and guidelines have emerged to refine recommendations for the use of radioactive iodine (RAI) therapy after thyroidectomy for cancer. We aim to describe national trends in RAI utilization, assess the impact of individual hospitals on RAI utilization, and examine whether variation in prescribing habits has declined over time.
Methods: The National Cancer Database (NCDB) was queried from 2004 to 2016 for patients with papillary thyroid cancer (PTC) who received total thyroidectomy. Trends were analyzed using Joinpoint analysis. Hospital-specific effects and variation in prescribing habits were assessed through a hierarchical, mixed regression model.
Results: RAI utilization declined from 61.0% in 2004 to 43.9% in 2016. RAI use declined most profoundly in patients with T1a, N0/X, M0 PTC without extrathyroidal extension (34.8% in 2004 to 9.5% in 2015), but continues to be used commonly in patients with advanced disease for whom it is routinely recommended (73.4% in 2004 to 72.0% in 2015). Furthermore, ∼80% of hospitals in 2016 utilized at or below the median utilization rate in 2006. Variation in RAI utilization across hospitals decreased by ∼50% from 2004 to 2016 (Levene's test p < 0.001), with a significant decline (p = 0.002) in the variation after 2012 (confidence interval: 2010 to 2014). Conclusions: Recommendations for whom to prescribe RAI appear to have impacted both the number of patients receiving RAI and the variation in prescribing habits across hospitals. Hospital selection has contributed less to the probability of receiving RAI over time.