Radioactive Iodine Improved Outcomes in Intermediate-Risk Thyroid Cancer

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Radioactive iodine therapy was associated with improved survival and reduced mortality risk.

New data have linked radioactive iodine (RAI) therapy with improved overall survival in patients with intermediate-risk papillary thyroid cancer.

The incidence of papillary thyroid cancer has increased dramatically in the past 2 decades, but long-term prognosis is very good with appropriate thyroidectomy, both with or without RAI therapy. The benefits of RAI therapy in certain patients, however, are somewhat less clear.

“The American Thyroid Association (ATA) currently recommends adjuvant RAI therapy for high-risk patients and select intermediate-risk cases, but not for low-risk patients,” the researchers wrote in the study, which was published in the Journal of Clinical Endocrinology & Metabolism.

“Adjuvant RAI therapy has been debated for intermediate-risk patients, as there is a paucity of data regarding the long-term prognosis of patients in this risk group.”

To expand their knowledge, the researchers analyzed adults with intermediate-risk papillary thyroid cancer who underwent total thyroidectomy with or without RAI who were included in the National Cancer Database from 1998 to 2006. Mean follow-up was 6 years.

Of 21,870 patients included in the study, 70.5% received RAI and 29.5% did not. Data from unadjusted analysis linked RAI to improved overall survival in all patients (P<.001).

Subgroup analyses yielded similar results. In patients aged younger than 45 years, RAI was associated with improved overall survival (P=.002). Most patients were alive at the study’s conclusion, however, and median survival could not be estimated. RAI also appeared to be associated with improved overall survival in patients aged 65 years and older (median, 140 months vs. 128 months; P=.008).

After adjustment for clinical and demographic factors, RAI was associated with a 29% reduced risk for death (P<.001) and a 36% reduced risk for death (P=.016) in patients aged younger than 45 years.

The researchers acknowledged the “generally favorable prognosis” for papillary thyroid cancer, but they also pointed out that their results regarding decreased mortality risk demonstrate the benefits of RAI in this patient population.

“Current ATA guidelines recommend RAI therapy in select intermediate-risk patients. While the decision to use adjuvant RAI therapy remains centered on individual patient and disease-specific factors, we hope that our findings will inform future guideline recommendations,” they wrote.


  1. Ruel E et al. J Clin Endocrinol Metab. 2015;doi:10.1210/jc.2014-4332.