Abstract PO-215: Racial disparities in proton beam therapy use for newly diagnosed cancer patients in the United States
Authors: Nogueira Leticia M. , Jemal Ahmedin , Efstathiou Jason A. , Yabroff K. Robin 
Published: January 2022

Background: Black patients are less likely than White patients in the US to receive guideline-concordant cancer care, including radiation therapy. Proton Beam Therapy (PBT) is a potentially superior technology to photon radiotherapy for the treatment of pediatric cancers, where decreasing late effects of radiation treatment is a main concern, and in cancers where pituitary, visual, auditory, and intellectual functions might be disrupted because of radiation therapy. The aim of this study was to conduct a comprehensive evaluation of racial disparities in PBT use in the US. Methods: We identified 4,919,975 Black and White patients diagnosed between 2004 and 2018 in the National Cancer Database (NCDB) based on data collected from Commission on Cancer (CoC) accredited hospitals. Once a patient is diagnosed and/or treated at a CoC accredited facility, the patient is followed and all treatment is reported (including treatment received outside of the reporting facility). Therefore, NCDB captures PBT received both at CoC-accredited hospitals (59.5% of patients who received PBT in this study) and PBT received at hospitals not accredited by CoCs (40.5% of PBT patients in this study). American Society of Radiation Oncology (ASTRO) Model Policies were used to classify patients into Group 1, for which PBT is the recommended radiation therapy modality, and Group 2, for which evidence of PBT efficacy is still under investigation. Propensity score matching was used to ensure comparability of Black and White patients' clinical characteristics and regional availability of PBT. Results: Black cancer patients were less likely to be treated with PBT than White cancer patients with similar characteristics (Odds Ratios [OR]: 0.72; 95% Confidence Interval [CI]: 0.68, 0.76). Racial disparities were greater for Group 1 cancers (OR = 0.61; CI: 0.54, 0.69) than for Group 2 cancers (OR: 0.75; CI: 0.70, 0.81). Disparities were greatest for Group 1 cancers commonly diagnosed in children, such as central nervous system (OR: 0.54; CI: 0.46, 0.63) and rhabdomyosarcoma (OR: 0.47; CI: 0.31, 0.70). Racial disparities in PBT receipt among Group 1 cancers increased during the study period and were greatest in 2018 despite the increase in the number of facilities offering PBT from 4 to 28 during the corresponding period, Conclusion and Relevance: Racial disparities in PBT receipt are greatest for cancers for which PBT is the recommended radiation therapy modality. The racial disparities identified in our study suggest undertreatment of Black patients with the greatest need (e.g. children diagnosed with central nervous system cancers). Future studies are needed to identify modifiable factors contributing to the racial disparity in receipt of PBT as efforts other than increasing the number of facilities providing PBT will be needed to eliminate disparities.

Citation Format: Leticia M. Nogueira, Ahmedin Jemal, Jason A. Efstathiou, K. Robin Yabroff. Racial disparities in proton beam therapy use for newly diagnosed cancer patients in the United States [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-215.