National patterns of care and predictors of neoadjuvant and concurrent chemotherapy use with definitive radiotherapy in the treatment of patients with oropharyngeal squamous cell carcinoma.

BACKGROUND: To the authors' knowledge, the patterns of care for the radiotherapy-based treatment of patients with stage III to IVB oropharyngeal squamous cell carcinoma (OPSCC) are poorly defined. The objective of the current study was to characterize the use and predictors of chemotherapy with radiotherapy for this population using the National Cancer Database. METHODS: Patients in the National Cancer Database with AJCC (American Joint Committee on Cancer) stage III to IV OPSCC who were treated with radiotherapy between 2003 and 2012 were eligible for analysis. Treatment was defined as radiotherapy alone, concurrent chemoradiotherapy, or induction chemotherapy (IC). Multivariable regression with multilevel modeling was used to determine predictors of any chemotherapy use and, among patients receiving chemotherapy, the predictors of IC. RESULTS: The majority (90%) of the 30,875 eligible patients received chemotherapy, the majority of whom (71% of the total) were treated with definitive chemoradiotherapy; a sizeable percentage of patients received IC (19% of total). On multivariable regression, younger age, favorable comorbidity status, and more advanced tumor and lymph node disease were found to be independent predictors of any chemotherapy and IC use. Nonwhite patients (odds ratio [OR], 0.71; P<.0001), women (OR, 0.74; P<.0001), and individuals without private insurance were found to be significantly less likely to receive chemotherapy. Patients treated at higher-volume institutions were significantly less likely to receive IC (OR, 0.69; P = .0006). Human papillomavirus status did not appear to independently influence treatment choice. CONCLUSIONS: The vast majority of patients with stage III to IVB OPSCC who were treated with definitive radiotherapy received chemotherapy, which is consistent with high-level data and national recommendations. However, disparities with regard to race, sex, and insurance status emerged thereby requiring additional investigation. The frequent use of IC despite limited supportive evidence warrants research on physician and patient decision making and presents an opportunity to improve evidence-based treatment delivery. Cancer 2017;123:273-282. © 2016 American Cancer Society.