Differential utilization of thyroid lobectomy after the 2015 American Thyroid Association guideline update

Background: The 2015 American Thyroid Association (ATA) guidelines added thyroid lobectomy (TL) as the appropriate treatment for low-risk differentiated thyroid cancer (DTC). We aimed to investigate the population-level factors that influence the utilization of TL. Methods: The Surveillance, Epidemiology and End Results (SEER) database was queried for all DTC patients fitting low-risk criteria as defined by the ATA. Trends in total thyroidectomy (TT) and TL were identified using a Cochrane– Armitage test. Multivariable logistic regression identified patient and socioeconomic characteristics associated with TL, and difference-in-difference analysis was used to control for secular trends over time. Results: A total of 43,526 patients with low-risk DTC were identified in the SEER database; 39,411 pre-2015 and 4115 post-2015. After 2015, TT continued to outnumber TL (76.2% vs 23.8%), although the rate of TL increased significantly (11.6% to 23.8%, P < 0.001). However, difference-in-difference analysis found that age > 55 (OR 1.11, 95% CI 1.01–1.19, P < 0.001) and rurality (OR 1.16, 95% CI 1.05–1.28, P < 0.001) were independently associated with TT. TL was associated with T1 disease (OR 1.11, 95% CI 1.04–1.19, P = 0.001). Conclusion: Although the 2015 ATA guideline update led to an increase in TL for low-risk DTC, most patients still underwent TT. Age and neighborhood significantly impact the odds of receiving guideline-appropriate TL for low-risk DTC, especially for T2 disease.