To identify variables associated with compliance to radiation therapy (RT) for treatment of head and neck cancer in a safetynet health system. Materials/Methods: We systematically screened electronic health record data from a large safety-net health system serving over 300,000 patients annually between October 2012 and August 2015 and identified 181 patients who were treated with radiation therapy (RT) in a curative approach for American Joint Committee on Cancer stage I-IV head and neck cancer. The number of days of missed treatments and reasons given for them by the patients were identified. Demographics, access to care, toxicity, drug use, comorbidities, psychiatric diagnosis, and treatment variables were analyzed for impact on compliance. Disease-free (DFS) and overall survival (OS) of patients with more than or fewer than 5 days of missed treatments were compared using Kaplan-Meier analyses. Results: A total of 181 patients (mean age 54.8 years) were identified who completed RT with curative intent, and 141 (77.9%) of these patients received chemotherapy (CT). Of these patients, 45 (31.9%) patients received induction CT, and 136 (96.4%) received concurrent CT. There were 166 patients (90.0%) who completed all fractions of RT, and 43 patients (23.8%) completed their RT with no missed days. There were 9240 total treatment days (mean of 51.1 treatment days), of which 844 (9.1%) were missed or delayed treatment days. Patient-offered reasons for the delay were classified as: failure to coordinate care (nZ34, 4.0%), transportation issues (nZ54, 6.4%), acute toxicity (nZ229, 25.9%), inclement weather (nZ20, 2.4%), comorbidities (nZ107, 12.7%), delays related to PFG feeding tubes (nZ18, 2.1%), tolerance to setup (nZ32, 3.8%), patient initiated (nZ209, 24.8%), and unknown (nZ150, 17.8%). Not owning a vehicle was associated with missing more days due to transportation issues (PZ.04). Male gender (PZ.017) and weight loss during radiation (PZ.029) were associated with more total missed days of radiation. Variables that were associated with 5 or more missed treatment days were the lowest Karnofsky Performance Status Score achieved during RT (PZ.002), maximum pain score during RT (PZ.042), skin sensation toxicity (PZ.008), history of methamphetamine abuse (PZ.009) (but not other substances), and multiagent induction CT (PZ.027). In patients whose RT treatment was completed with fewer than or exactly 5 days of delay, DFS was improved by 9.4 months (22.5 vs 13.1, PZ.012), and OS was improved by 7.0 months (28.2 vs 15.3, PZ.0001). Conclusion: This study concurs with past studies that missing treatments is detrimental to overall survival. Therefore, it is prudent in a safety-net hospital to identify specific barriers to treatment compliance in order to design optimal interventions, such as a questionnaire that identifies highrisk patients so that we can intervene by allocating resources appropriately in order to improve outcomes.
