title: Trends and Predictors of Chemotherapy Use among Thyroid Cancer Patients in the National Cancer Database (2004-2013).
abstract: OBJECTIVE
  Beginning in 2011, the Food and Drug Administration (FDA) approved the use of multikinase inhibitors (MKIs) for medullary thyroid cancers (MTCs), and in 2013 MKIs were approved for metastatic differentiated thyroid cancers (DTCs). However, little is known about the use of chemotherapy in thyroid cancer patients. Thus, the goal of our study was to describe patterns of chemotherapy use, including MKIs, among DTC and MTC patients in the National Cancer Database (NCDB).
  
  
  METHODS
  Chemotherapy use, along with other treatment types (surgery and radiation), was assessed between 2004 and 2013. The primary predictor was the year of diagnosis (2004-2010 and 2011-2013), based on the FDA's approval of chemotherapy for MTC (2011). Baseline use of MKIs in DTCs in 2013 was also examined. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% CI of receipt of chemotherapy.
  
  
  RESULTS
  Overall, 199,654 patients were included in our analytic sample with 194,667 nonmetastatic DTCs, 1,633 metastatic DTCs, and 3,354 MTCs. Among MTCs, chemotherapy use significantly increased from 3.1% in 2004-2010 to 5.0% in 2011-2013 (p = 0.018) in unadjusted and adjusted (OR = 1.54, 95% CI: 1.00, 2.36) analyses. In metastatic DTCs, 4.9% of patients received chemotherapy in 2013, which was not significantly higher than in previous years (p = 0.755).
  
  
  CONCLUSIONS
  Overall, chemotherapy use among MTCs increased marginally following the FDA's approval of MKIs in 2011, although their use remains very low. MKIs were infrequently used in metastatic DTCs in 2013. Future studies examining patterns of chemotherapy in thyroid cancer patients are warranted.
authors.affiliation: Surveillance and Health Services Research, American Cancer Society, Emory University School of Medicine, Atlanta, Ga., USA.
authors.forename: Stacey A
authors.initials: SA
authors.lastname: Fedewa
authors.affiliation: Surveillance and Health Services Research, American Cancer Society, Emory University School of Medicine, Atlanta, Ga., USA.
authors.forename: Ahmedin
authors.initials: A
authors.lastname: Jemal
authors.affiliation: Department of Otolaryngology, Emory University School of Medicine, Atlanta, Ga., USA.
authors.forename: Amy Y
authors.initials: AY
authors.lastname: Chen
keywords: Differentiated thyroid cancers; Medullary thyroid cancer; Multikinase inhibitor