Association Between Implementation of the 2009 American Thyroid Association Guidelines and De-escalation of Treatment for Low-risk Papillary Thyroid Carcinoma

De-escalation of therapy for papillary thyroid carcinoma (PTC) has been evolving in American Thyroid Association (ATA) guidelines for patients with ATA low-risk category cancers, ie, patients with PTC tumors of 4 cm or smaller, and with no clinically-positive lymph nodes or extrathyroidal extension (ETE). In 2009, radioactive iodine (RAI) ablation was no longer recommended for patients with tumors smaller than 1 cm; hemithyroidectomy, or at most total thyroidectomy, was endorsed. For patients with larger tumors (1-4 cm), hemithyroidectomy or total thyroidectomy (with or without RAI) were still options.¹ To our knowledge, the outcomes of these de-escalation recommendations on the rates of hemithyroidectomy, total thyroidectomy, and total thyroidectomy with RAI for low-risk PTC have not been studied. In 2015, newer guidelines recommending further de-escalation for patients with low-risk disease were published,² and although National Surgical Quality Improvement Program data evaluated outcomes, population-level data are not yet available.³ We evaluated rates of various treatment options before and after publication of the 2009 guidelines using Surveillance, Epidemiology, and End Results (SEER) data available through 2016. We examined 2 groups of patients with low-risk disease: those with tumors of 1 cm or smaller and those with tumors 1 to 2 cm. Although guidelines make recommendations for low-risk tumors up to 4 cm, we chose to examine trends in patients with tumors only up to 2 cm because there should be less debate about adhering to guideline recommended de-escalation for these patients.

Following institutional review board approval from the Memorial Sloan Kettering Cancer Center, we used the SEER Database of the National Cancer Institute and SEER*Stat software (version 8.3.4) to obtain raw numbers of patients in each tumor size range and to calculate rates of each treatment option. We excluded patients with ETE using both the local tumor spread and thyroid-specific CS extension variables, and also excluded patients with either clinically or pathologically positive nodes.

For tumors of 1 cm or smaller, there was a minimal increase in guideline-recommended hemithyroidectomy rates before and after the 2009 guidelines, from 20.5% in 2008 to 26.9% in 2016. There was a corresponding decrease in the rate of total thyroidectomy, especially total thyroidectomy with RAI, from 18.9% in 2008 to 7.1% in 2016. Nonetheless, in 2016, 73.1% of patients were still being treated with total thyroidectomy with or without RAI (Figure).

Tumors 1 to 2 cm were overall treated more aggressively than tumors of 1 cm or smaller, but similar trends of de-escalation were seen. There was a minimal increase in hemithyroidectomy rates before and after the 2009 guidelines, from 5.7% in 2008 to 11.4% in 2016. There was a larger decrease in the rate of total thyroidectomy with RAI, from 34.6% in 2008 to 21.9% in 2016. There was a corresponding increase in the rate of total thyroidectomy without RAI, from 59.7% in 2008 to 66.7% in 2016.

The 2009 ATA guidelines endorsed hemithyroidectomy as sufficient treatment for small (<1 cm) tumors but did not strongly recommend against total thyroidectomy. For tumors larger than 1 cm, guidelines more strongly endorsed total thyroidectomy without RAI as sufficient treatment for larger tumors. Our analysis found that the stronger guideline statement had a larger effect: for patients with tumors smaller than 1 cm, 73.1% were still treated with total thyroidectomy with or without RAI in 2016. For tumors 1 to 2 cm, use of total thyroidectomy with RAI dropped to 21.9% of all patients in 2016. These trends suggest that ATA guidelines do appropriately influence practice patterns with an acceptable time lag, and that for de-escalation efforts to work, stronger guideline recommendations are more effective. The 2015 guidelines contain stronger de-escalation recommendations and should be expected to further change practice.

Accepted for Publication: August 31, 2020.

Corresponding Author: Benjamin R. Roman, MD, MSHP, Head and Neck Service, Memorial Sloan Kettering Cancer Center, 1275 York Ave, Rm C-1075, New York, NY 10065 (romanb@mskcc.org).

Published Online: October 1, 2020. doi:10.1001/jamaoto.2020.3024

Author Contributions: Dr Roman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Lohia, Roman.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Lohia, Roman.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Lohia, Roman.

Administrative, technical, or material support: Roman.

Supervision: Morris, Roman.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported in part by the Cancer Center Support Grant P30 CA008748 from the National Institutes of Health/National Cancer Institute.

Role of the Funder/Sponsor: The National Institutes of Health/National Cancer Institute had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.