Racial Disparities in Differentiated Thyroid Cancer: Have We Bridged the Gap?

Background: Racial disparities in the management of differentiated thyroid cancer (DTC) exist in the United States. There is a paucity of data examining their temporal trends. It was hypothesized that racial disparities in care provided to patients with DTC have improved over the past 15 years. Methods: Adult patients undergoing surgery for DTC were included from the National Cancer Data Base (1998-2012). Temporal trends in appropriate extent of thyroidectomy and radioactive iodine therapy (RAI) were described for different racial groups. Multivariable logistic regression models were employed to estimate the adjusted association of receipt of appropriate extent of surgery and RAI, specifically under- and over-treatment, among different racial groups. Results: Among 282,043 DTC patients, 80.3% were non-Hispanic white (white), 8.1% Hispanic, 7.2% non-Hispanic black (black), and 4.4% Asian. Black versus white race/ethnicity was associated with lower odds of receiving appropriate surgery (odds ratio [OR]=0.78 [confidence interval (CI) 0.71-0.87]; p<0.001). Appropriate RAI treatment was higher in blacks (OR=1.07 [CI 1.02-1.12]; p=0.01) and lower for Hispanics (OR=0.90 [CI 0.86-0.95]; p<0.001) compared with whites. There was a higher likelihood of RAI under-treatment in minority groups (Hispanic OR=1.27, black OR=1.26, Asian OR=1.25; p<0.001), and a lower likelihood of RAI over-treatment (Hispanic OR=0.89, black OR=0.83, Asian OR=0.79; p<0.001) compared with whites. Over time, an increasing proportion of black and white patients underwent appropriate extent of thyroidectomy (1998 vs. 2012: 78% vs. 88% and 81% vs. 91%, respectively). Compared with 1998, fewer patients in 2012 were under-treated with RAI: whites (48% vs. 29%, respectively), blacks (51% vs. 33%), Hispanics (51% vs. 37%), and Asians (55% vs. 39%). The extent of RAI over-treatment increased (1998 vs. 2012): whites (1% vs. 4%), blacks (2% vs. 4%), Hispanics (2% vs. 4%), and Asians (2% vs. 3%), respectively. Conclusions: Appropriate utilization of surgery and RAI for DTC has improved over time. However, the proportion of patients receiving appropriate thyroid surgery is consistently lower for blacks compared with whites. RAI over-treatment increased for all races over the study period. Efforts are needed to standardize DTC care among minority patients.