Standard but Not Equal: Disparities in Advanced Radiotherapy Techniques for Head and Neck Cancer in the United States

Abstract

<h3>Purpose/Objective(s)</h3> Advanced radiotherapy techniques (ART), including intensity-modulated radiotherapy (IMRT) and proton beam therapy (PBT), offer enhanced conformality, can reduce acute and late toxicities from radiotherapy for head and neck cancers (HNC), and are considered standard-of-care by consensus guidelines. This study aims to characterize implementation of ART and corresponding patterns of care in the United States since 2004. <h3>Materials/Methods</h3> Data for patients treated with external beam radiotherapy for primary HNC (any histology) were extracted from the National Cancer Database (2004-2017). Cases with metastatic disease and early stage glottic larynx cancer (Tis-T2,N0) were excluded. ART was defined as radiotherapy delivery with either IMRT or PBT, while non-ART encompassed 2D or 3D-conformal techniques. Sociodemographic, facility-specific, and clinical associations with receipt of ART were assessed by logistic regression. <h3>Results</h3> 177,373 patients with HNC were eligible for analysis; 94.2% received ART (IMRT: 93.3%, PBT: 0.9%), and 5.8% received non-ART. ART utilization increased substantially from 3,317 (78.0%) in 2004 to 14,088 (96.0%) in 2012 (p<0.001), largely driven by adoption of IMRT (77.0% to 95.7%). Use of ART increased slightly between 2012 and 2017 (96.0% to 96.9%; p<0.001), driven by growth in PBT (0.3% to 2.7%; p<0.001). On multivariable logistic regression, black patients were less likely to receive ART (OR 0.87; 95%CI 0.80-0.94), as were older patients (continuous OR 0.95; 95%CI 0.93-0.96), the uninsured (OR 0.70; 95%CI 0.63-0.78), and those with Medicaid (OR 0.80; 95%CI 0.74-0.87). Patients undergoing care at treatment facilities in the Northeast or Midwest, of non-academic affiliation, and with lower HNC volume were also less likely to receive ART. Census-tract level measures of income and educational attainment were directly correlated with receipt of ART. Likewise, nasopharyngeal or oropharyngeal primary site, advanced T- or N-classification, and receipt of chemotherapy or surgery were each independently associated with receipt of ART. <h3>Conclusion</h3> ART utilization has increased since the early 2000's, driven initially by IMRT and more recently by PBT. Despite the near-ubiquity of ART today, we identified racial, socioeconomic, and geographic disparities in their adoption, potentially exposing disadvantaged patients to preventable toxicity and quality-of-life insults from non-ART.