Abstract C80: Compliance with head and neck radiotherapy in medically insured and uninsured cancer patient populations
Authors: Thomas Kimberly M. , Martin Travis , Wilhelm Holly , Gao Ang , Ahn Chul , Schwartz David L. 
Published: May 2016

Abstract
Background: Head and neck cancer is a curable malignancy. However, treatment is complex, costly, and toxic. Radiotherapy is a cornerstone of treatment, requiring 30-35 daily treatments over 6-7 weeks. Diligent patient compliance is crucial; unplanned treatment interruptions reduce cure rates. Compliance tracks closely with a complex mix of treatment and human factors, including patient trust in providers, effectiveness of toxicity management, and quality of social support. Previous studies suggest that medically underserved populations experience higher rates of radiation non-compliance. We studied compliance rates and potential confounding factors in medically insured and uninsured populations served by a single academic health system.
Methods: We retrospectively analyzed electronic medical and billing records of head and neck radiotherapy patients referred from 1) the University of Texas Southwestern (UTSW) Medical Center and 2) Parkland Hospital (PHHS), which provides indigent care to Dallas County, Texas. Eligible diagnoses included cancers of the nasopharynx, base of tongue, salivary, paranasal sinus, tonsil, oropharynx, oral cavity, larynx, or hypopharynx. We identified 564 analyzable cases from a total of 722 treated from January 2011 through December 2014. For initial analysis, patients who missed any scheduled treatment were considered “noncompliant”. Subsequent analysis included number of missed treatment days, reasons for missed treatment, multivariate modeling of patient/ treatment variables, and downstream survival outcomes.
Results: Three-hundred sixteen (56%) of study patients missed treatment; 114 missed a single session, while 202 missed multiple treatments. Median number of missed treatments was 2 days (lowest 25% interquartile = 1 missed day, 50% interquartile = 2 days, 75% interquartile = 5 days). One-hundred fifty two (70%) PHHS patients were non-compliant vs. 163 (47%) UTSW patients. Stepwise logistic regression analyses identified patient age (p=0.016), use of chemotherapy (p=0.021), and referral location (p=0.0002) was predictive for patient cancellation of treatment. UTSW patients enjoyed a 53.7% less frequent cancelation rate than PHHS patients after controlling the effect of age and chemotherapy. Age (p=0.026), chemotherapy (p=0.005), and referral location (p&lt;0.0001) were also significantly associated with patient no-shows. Referral location (p=0.0007) was the only significant factor associated with total number of missed visits. PHHS patients suffered 1.72 more interrupted days than UTSW patients. Among non-compliant patients, there was a significant difference in time to local recurrence between UTSW and PHHS patient cohorts (p=0.013 by log-rank test).
Conclusions: We demonstrate significant disparity in patient compliance to radiation treatment across privately insured and indigent populations managed within a single academic health system. Poor compliance was tracked with expected factors, such as advanced age and treatment intensity (e.g. combined use of chemotherapy with radiation), but was associated most closely with indigent care. Missed treatment predicted for poor local disease control, but only in the PHHS subgroup, suggesting that disease control tracks with high-risk social/treatment factors impacting uninsured patients, rather than secondary time delays themselves. This retrospective study cannot establish causative mechanisms linking uninsured status with non-compliance or disease outcomes, but confirms a pressing need to design interventions to break social/behavioral cycles corrupting cancer care in disadvantaged populations.
Citation Format: Kimberly M. Thomas, Travis Martin, Holly Wilhelm, Ang Gao, Chul Ahn, David L. Schwartz. Compliance with head and neck radiotherapy in medically insured and uninsured cancer patient populations. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C80.