Trends and Disparities of Proton Therapy Use among Patients with Head and Neck Cancer: Analysis from the National Cancer Database (2005-14).

Purpose The purpose of this study was to analyze national trends and disparities in proton therapy use among patients with head and neck cancer receiving radiotherapy to primary disease sites. Patients and Methods Using the National Cancer Database, we identified patients diagnosed with any nonmetastatic head and neck primary malignancy between 2005 and 2014 who were treated with radiation therapy or proton therapy directed specifically at the primary disease site. Distributions of patient and clinical factors between the two groups were evaluated. Multivariable logistic regression was used to correlate factors associated with proton therapy use compared with other modalities of radiation therapy. Results There were 220 491 patients who received any radiation therapy as part of their initial treatment course, only 417 (0.2%) of whom received proton therapy. The use of protons underwent a small increase from 0.13% in 2005-06 to 0.41% by 2013-14 (P < .001). The most common primary sites treated with proton therapy were the nasal cavity/nasopharynx (n = 151, 36.2%) and the oral cavity (n = 98, 23.5%). Most patients had T4 disease (n = 94, 31.0%). On multivariable logistic regression, all primary sites compared with hypopharynx/larynx sites (odds ratio [OR], 2.53-10.53; P < .001), treatment at an academic facility (OR, 2.54; P < .001), ≥ 13-mile distance from the treating facility (OR, 1.94; P < .001), and highest median household income quartile (> $63 000; OR, 2.52; P = .002) were associated with an increased likelihood of receiving proton therapy. Conclusion Proton use has undergone an incremental increase in the United States but remains an uncommon modality for the treatment of primary head and neck cancer.