Background: Anaplastic thyroid cancer (ATC) is the rarest type of thyroid cancer and has the lowest overall survival. To the authors' knowledge, the impact of socioeconomic status and race/ethnicity has not yet been described.

Methods: Data regarding 719 patients diagnosed with their first primary malignant ATC from January 1, 1998 to December 31, 2011 in the Surveillance, Epidemiology, and End Results program registries were examined. Differences in receipt of thyroidectomy, radiotherapy, and lymph node examination were examined by race/ethnicity. Survival also was examined by race/ethnicity.

Results: Nearly 70% of patients were non-Hispanic white, and 55.4% of patients received treatment. Tumor size (P = .13), lymph node involvement (P = .60), and residence in high poverty neighborhoods (P = .08) did not vary by race/ethnicity. Nonwhite patients were more likely to receive no treatment (adjusted odds ratio, 0.29; 95% confidence interval [95% CI], 0.16-0.54). When receipt of radiotherapy was adjusted for, nonwhite patients had a higher risk of overall death (adjusted hazards ratio [aHR], 1.24; 95% CI, 1.01-1.54), although not disease-specific death (aHR, 1.14; 95% CI, 0.92-1.42). Patients living in areas of high poverty had lower overall survival (aHR, 1.54; 95% CI, 1.09-2.18) and disease-specific survival (aHR, 1.68; 95% CI, 1.19-2.36).

Conclusions: In this population-based study of patients with ATC, nonwhite patients were found to be less likely to receive treatment. Furthermore, nonwhite patients had poorer overall survival, and patients living in areas of high poverty had both worse overall and disease-specific survival. Racial/ethnic and socioeconomic disparities appear to exist in the treatment and survival of patients with ATC. Cancer 2018;124:1780-90. © 2018 American Cancer Society.