Racial and Ethnic Disparities in Appropriate Thyroid Cancer Treatment, Before and After the Release of the 2015 American Thyroid Association Guidelines

BACKGROUND

The 2015 American Thyroid Association (ATA) guidelines reduced the recommended extent of therapy for low-risk thyroid cancers. Little is known about the impact of these changes on overall treatment patterns and on previously described racial/ethnic disparities in guideline-concordant care. This study aimed to assess trends in thyroid cancer care before and after release of the 2015 guidelines, with particular attention to racial/ethnic disparities.

METHODS

Patients with well-differentiated thyroid cancer were identified from the National Cancer Database (2010-2018). An interrupted time series design was used to assess trends in treatment before and after the 2015 guidelines. Appropriateness of surgical and radioactive iodine (RAI) treatment was determined based on the ATA guidelines, and the likelihood of receiving guideline-concordant treatment was compared between racial/ethnic groups.

RESULTS

The study identified 309,367 patients (White 74%, Black 8%, Hispanic 9%, Asian 6%). Between 2010 and 2015, the adjusted probability of appropriate surgery was lower for Black (- 2.1%; p < 0.001), Hispanic (- 1.0%; p < 0.001), and Asian (- 2.1%; p < 0.001) patients than for White patients. After 2015, only Hispanic patients had a lower probability of undergoing appropriate surgical therapy (- 2.6%; p = 0.040). Similarly, between 2010 and 2015, the adjusted probability of receiving appropriate RAI therapy was lower for the Hispanic (- 3.6%; p < 0.001) and Asian (- 2.4%; p < 0.001) patients than for White patients. After 2015, the probability of appropriate RAI therapy did not differ between groups.

CONCLUSIONS

Between 2010 and 2015, patients from racial/ethnic minority backgrounds were less likely than White patients to receive appropriate surgical and RAI therapy for thyroid cancer. After the 2015 guidelines, racial/ethnic disparities in treatment improved.

Change in Practice of Radioactive Iodine Administration in Differentiated Thyroid Cancer: A Single-Centre Experience

OBJECTIVE

Our study aimed to analyse temporal trends in radioactive iodine (RAI) treatment for thyroid cancer over the past decade; to analyse key factors associated with clinical decisions in RAI dosing; and to confirm lower activities of RAI for low-risk patients were not associated with an increased risk of recurrence.

METHODS

Retrospective analysis of 1,323 patients who received RAI at a quaternary centre in Australia between 2008 and 2018 was performed. Prospectively collected data included age, gender, histology, and American Joint Committee on Cancer stage (7th ed). American Thyroid Association risk was calculated retrospectively.

RESULTS

The median activities of RAI administered to low-risk patients decreased from 3.85 GBq (104 mCi) in 2008-2016 to 2.0 GBq (54 mCi) in 2017-2018. The principal driver of this change was an increased use of 1 GBq (27 mCi) from 1.3% of prescriptions in 2008-2011 to 18.5% in 2017-2018. In patients assigned as low risk per ATA stratification, lower activities of 1 GBq or 2 GBq (27 mCi or 54 mCi) were not associated with an increased risk of recurrence. In patients assigned to intermediate- or high-risk categories who received RAI as adjuvant therapy, there was no difference in risk of recurrence between 4 GBq (108 mCi) and 6 GBq (162 mCi).

CONCLUSIONS

Our data demonstrate an evolution of RAI activities consistent with translation of ATA guidelines into clinical practice. Use of lower RAI activities was not associated with an increase in recurrence in low-risk thyroid cancer patients. Our data also suggest lower RAI activities may be as efficacious for adjuvant therapy in intermediate- and high-risk patients.

The impact of radioactive iodine treatment on survival among papillary thyroid cancer patients according to the 7th and 8th editions of the AJCC/TNM staging system: a SEER-based study

Papillary thyroid cancer is a very common endocrine malignancy. The 8th American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system introduced major changes. We conducted this retrospective cohort analysis to assess the benefits of radioactive iodine (RAI) according to different stratification of patients. The source of the data was the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. From 2006 to 2015, patients with papillary thyroid cancer were included in our study. The interactions between different variables and RAI treatment were tested by multivariate Cox regression models to compare the survival differences according to RAI treatment between the patients assessed with the 7th and 8th edition of the AJCC/TNM staging system. The results of the interaction analysis and group comparisons indicated that the effects of RAI treatment on patients staged with the 7th and 8th editions were similar. Patients with early Stage, early T stage, N0 and subtotal or near total thyroidectomy benefited greatly from RAI treatment. Patients with Stage III according to the 8th edition benefited less from RAI than patients with Stage III according to the 7th edition. Patients with T1a benefited from RAI but benefited less than patients with other T stages. Patients with T3a benefited more from RAI than those with T3b. According to the 8th edition, Stage III/IV more accurately differentiates patients with advanced stage disease. These patients benefitted less from RAI treatment, which may be due to the relatively weaker iodine uptake by tumor cells. T1a patients benefitted less than patients with other T stages. The difference in RAI benefit between patients with T3a and T3b is a novel finding in our study.