Abstract A098: Socioeconomic and geographic predictors for radiotherapy quality disparities in the Mid-Southern U.S.
Authors: Wakefield Daniel V. , Carnell Matthew , Dove Austin P.H. , Delavega Elena , Ozdenerol Esra , Pisu Maria , Martin Michelle Y. , Schwartz David L. 
Published: August 2020

Background: Approximately half of cancer patients are prescribed radiotherapy (RT) during their care. RT noncompliance (NC) is a well-studied quality measure associated with inferior survival. Cancer outcomes in the Mid-South (West Tennessee, Mississippi Delta, Eastern Arkansas) rank well below other U.S. regions. The purpose of this study is to benchmark RT NC rates, define socioeconomic predictors of RT NC, and geographically map NC across a large Mid-Southern catchment region served by a single academic cancer referral center.

Methods: Demographic, clinical, and treatment information were collected for all patients treated with RT at the University of Tennessee West Cancer Center from January 1, 2015 to December 31, 2017. RT NC was defined as delay in 2 or more treatments. “Critically high” RT NC was defined as delay in 5 or more treatments. Patients with Medicaid or no insurance were categorized as “At Risk.” Patient predicted income (PPI) was modeled using 2016 US Census data for patient residence zip code and grouped by thirds into three (low, middle, and high) income categories. RT NC was compared by insurance type, race, and PPI, analyzed for significance using Pearson's Chi square testing, and geomapped by patient residence zip code and urban and rural status.

Results: A total of 3,754 patients were included, of whom 1,981 (52.8%) were Caucasian, 1,582 African American (42.2%), and 217 (5.7%) other. Insurance status was defined as Commercial, Medicare, or At Risk in 1,803 (48%), 1,508 (40%), and 443 (12%) patients, respectively. Overall, RT NC was seen in 962 patients (25.6%) and critically high RT NC was seen in 422 patients (11.2%). At-risk patients experienced more RT NC (36.2% v 25.1% p=&lt;0.001) and more than double the critically high RT NC compared to patients with commercial insurance (20.3% v 9.6% p=&lt;0.001). African American patients in our population experienced higher rates of RT NC and critically high RT NC compared to Caucasian patients ([30.5% v 22.0% p=&lt;0.001] and [14.9% v 8.8% p=&lt;0.001]). Compared to patients with high PPI (&gt;67k), patients with low PPI (&lt;$34k) experienced higher RT NC (20.2% v 31.7% p=&lt;0.001) and critically high RT NC (7.3% v 15.7% p=&lt;0.001). High RT NC rates were geographically associated with patients living in rural zip codes, with critically high RT NC rates in urban zip codes with low PPI.

Conclusion: In our high-volume academic radiotherapy practice, RT noncompliance correlates significantly with uninsured or Medicaid coverage status, African American race, and low predicted income. Noncompliance disproportionately impacts rural patients and inner-urban patients with low predicted income. Further studies are needed to understand causative mechanisms requiring intervention to help close gaps in radiotherapy quality.

Citation Format: Daniel V. Wakefield, Matthew Carnell, Austin P.H. Dove, Elena Delavega, Esra Ozdenerol, Maria Pisu, Michelle Y. Martin, David L. Schwartz. Socioeconomic and geographic predictors for radiotherapy quality disparities in the Mid-Southern U.S. [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr A098.