A National Cancer Disparities Analysis of Predictors for Radiation Therapy Refusal by Race.

PURPOSE

Radiation therapy (RT) refusal by patients with cancer is infrequent but is significant because it portends poor outcomes. No prior study has evaluated all five federally defined racial categories with respects to RT refusal. Here we use a large nationally representative population with cancer to determine: 1) which race of patients refuse RT the most and 2) predictive factors for RT refusal by race.

MATERIALS/METHODS: A retrospective study included patients ≥18 years old with diagnostically confirmed cancer between 2004-2017, using the National Cancer Database. All patients included were offered RT for first course treatment. Multivariable logistic regression assessed RT refusal (adjusted odds ratio [aOR]) with 95% confidence intervals (95%CI). Analyses were adjusted for patient factors (age, rurality, income, education, and comorbidities) and cancer characteristics (stage, cancer type, facility type, year of diagnosis, and region). Median overall survival was calculated using the Kaplan-Meier method.

RESULTS

Of 11,609,044 patients, 2,759,753 patients were included and recommended for RT by the treating physician. Median follow-up was 50 months. RT was refused by 139,383 patients (5.0%), varying by race: 416 NHPI (7.2%), 489 AIAN (5.8%), 118,186 Non-Hispanic White (5.0%), 17,427 Black (4.8%), and 2,865 Asian (4.8%) patients. The rates of annual RT refusal were increasing, especially among NHPI patients. The populations with the highest likelihood of refusing RT were NHPI (aOR=1.53, 95%CI=1.36-1.71), AIAN (aOR=1.24, 95%CI=1.12-1.37), and Black (aOR=1.11, 95%CI=1.09-1.14) patients, compared to Non-Hispanic White patients. Older age and higher comorbidity burden predicted RT refusal across all races. Median overall survival was 81 months and 144 months for patients who refused RT and received RT, respectively.

CONCLUSIONS

Indigenous and Black patients are more likely to refuse RT, which may contribute to inferior cancer outcomes. Understanding NHPI and AIAN patient perspectives and perceptions may elucidate interventions to mitigate these disparities.