A National Cancer Disparities Analysis of Pacific Islanders Who Decline Radiation Therapy and Impacts on Overall Survival

Abstract

<h3>Purpose/Objective(s)</h3> Native Hawaiians and Other Pacific Islanders (NHPI) face significant cancer health disparities. Declining cancer treatment is complex and associated with inferior outcomes. Understanding populations that decline radiation therapy (RT) may provide insight into improving cancer disparities. We investigated 1) whether NHPI decline RT at higher rates than other races, 2) the impact of declining RT on overall survival (OS), and 3) the factors associated with declining RT. <h3>Materials/Methods</h3> A retrospective cohort study of the National Cancer Database was conducted using a US hospital-based population including patients ≥18 years old with diagnostically confirmed lung, breast, prostate, rectal, liver, or endometrial cancer, diagnosed between 2004-2017. All patients were offered cancer RT. Declining treatment was defined as RT "recommended by the patient's physician, but was refused by the patient, the patient's family member, or the patient's guardian." Binomial logistic regression compared patients who declined RT versus accepted RT reported as odds ratios (OR) with 95% confidence intervals (95%CI). Cox proportional hazard models assessed OS with hazards ratios (HR). Analyses were adjusted for patient factors (age, urban/rural, income, education, comorbidities) and cancer characteristics (stage, pathology, treatment facility). A P<.05 threshold was used for co-variable selection into multivariable models. <h3>Results</h3> Of 5,229,314 patients eligible, 2,441,471 patients had a documented recommendation for RT. Median follow-up was 55 months. Patients were most often female (67%), white (84%), from metropolitan areas (84%), and insured by Medicare/Medicaid (52%). Cancer types included breast (53%), lung (19%), prostate (18%), rectal (5%), endometrial (4%), and liver (<1%) cancers, of which most (72%) were early-stage disease. 120,291 patients (5%) were documented as declining RT. Compared to white patients, the racial group with the highest risk for declining RT was NHPI (adjusted OR [aOR]=1.52, 95%CI=1.35-1.72), Table. Declining RT among NHPI was associated with poor OS (adjusted HR [aHR]=1.58, 95%CI=1.28-1.95), compared to NHPI patients who accepted RT. Factors associated with NHPI declining RT included patient age (aOR=1.04 per year, 95%CI=1.02-1.05), having any co-morbidities (aOR=1.62, 95%CI=1.28-2.05), breast cancer (aOR=1.82, 95%CI=1.2-2.85), and treatment at either a comprehensive community cancer center (aOR=1.55, 95%CI=1.20-2.01) or an integrated cancer center (aOR=1.89, 95%CI=1.30-2.72). <h3>Conclusion</h3> NHPI patients who decline RT have poor survival outcomes. Understanding NHPI patient perspectives and perceptions may elucidate interventions to mitigate these disparities. Investigating the intersection of culture and healthcare perceptions among NHPI patients is warranted.