Routine radioactive iodine (RAI) ablation for low-risk differentiated thyroid cancer (DTC) has decreased over time, yet some patients continue to receive this treatment unnecessarily, according to a study recently published in The Journal of Clinical Endocrinology & Metabolism.
Researchers led by Masha J. Livhits, MD, of UCLA David Geffen School of Medicine in Los Angeles, write that RAI ablation for low-risk DTC isn’t supported by current practice guidelines, so they wanted to look at the trends and drivers for such a treatment.
The team conducted a retrospective study of patients in California with low-risk DTC, analyzing data from 1999 to 2015. “Of 46,906 patients with DTC who underwent near-total or total thyroidectomy (mean age 48.2±15.5 [SD] years, 77% female), 25,457 (54%) received RAI,” the authors write. “The proportion of patients with regional/distant disease who received RAI remained stable at 68%. Utilization of RAI for patients with localized disease (no extrathyroidal extension, lymph node or distant metastases) decreased from 55% (1999) to 30% (2015), with the most significant change occurring in tumors <1 cm (39% to 11%). The rate also decreased for localized tumors between 1-2 cm (62% to 34%) and 2-4 cm (67% to 49%), and remained stable at 59% for tumors >4 cm. In multivariable analysis, patients with localized disease were less likely to receive RAI if they were >65 years old (OR 0.77, 95% CI: 0.71-0.83), had tumors <1 cm (OR 0.33, 95% CI: 0.31-0.35), or were treated in an academic hospital (OR 0.71, 95% CI: 0.67-0.75).”
The researchers write that these findings are a departure from other studies that found increases in RAI use from 1990 to 2008, but the routine use of RAI ablation for low-risk DTC was first discouraged in the 2009 American Thyroid Association guidelines. “To our knowledge, this is the first population level study assessing the potential impact of the 2009 ATA guidelines on RAI use,” they write. “We found that the rate of RAI decreased significantly following 2009 for patients with localized tumors <2 cm,” but many patients still underwent potentially unnecessary RAI ablation for tumors >2 cm.”
The authors conclude that there has been a decrease in this treatment over time. And yet, many patients still receive unnecessary RAI ablation for low-risk DTC between 2 and 4 cm, despite the 2009 guidelines.