Have 2006 ATA practice guidelines affected the treatment of differentiated thyroid cancer in the United States?

BACKGROUND

There is wide variability in the degree of adherence to guideline recommendations among caregivers. Our aim was to determine the clinical impact of the 2006 guidelines from the American Thyroid Association (ATA) on the management of differentiated thyroid cancer (DTC) in the United States.

METHODS

The Surveillance, Epidemiology and End Results (SEER) database (2004-2009) was employed. Patients were divided into two groups based on receipt of care before (DTC 04-06) and after (DTC 07-09) the release of the 2006 ATA guidelines. Adherence was determined with a chi-square test and binary logistic regression. Survival was analyzed with the Kaplan-Meier method and log-rank test.

RESULTS

A total of 12,816 patients with DTC were identified between 2004 and 2006, and 14,514 between 2007 and 2009 (DTC 07-09). Adherence to Recommendation 26 (surgery) tended to increase in DTC 07-09 (82.2% vs. 83.2%, p=0.083). Factors associated with discordant practice among the DTC 07-09 group were older age, treatment in the Northeast, having more than one primary cancer, tumor size >4 cm, and follicular and Hürthle cell histologies. Factors associated with accordance were treatment in the Midwest, level II-VI metastases, having lymph nodes examined, AJCC Stage III, and presenting with distant metastases. Patients treated in accordance with Recommendation 26 showed prolonged disease-specific survival (p<0.001). A trend toward more adherence to Recommendation 27 (lymphadenectomy) was observed over time (68.4% vs. 69.7%, p=0.065). Adherence to Recommendation 27 was not associated with disease-specific survival (p=0.539). Less discordance from guidelines was seen for cancers that were 2.1-4 cm, extrathyroidal, and greater than Stage I. Overall accordance with Recommendation 32 (radioactive iodine [RAI] ablation) increased in DTC 07-09 compared to DTC 04-06 (61.7% vs. 57.5% respectively, p<0.001), and this was associated with improved disease-specific survival in DTC 07-09 (p<0.001). Predictors of care discordant with guidelines were patient age ≥ 65 years, living in the Northeast, and not undergoing total thyroidectomy. Factors associated with RAI use in accordance with guidelines were married status, treatment in the South, and having more than one lymph node examined.

CONCLUSIONS

Care in accordance with evidence-based guidelines for DTC is associated with improved patient outcomes. Ongoing efforts should be undertaken to propagate guidelines to reduce variation in care and improve overall quality of care.