Introduction: The rate of refusal of chemotherapy ranges from 3% to 19%, but varies widely by patient profile and treatment setting. Using a large national registry, we explore factors significantly associated with the decision to decline chemotherapy in patients with early-stage, HR+/HER2- breast cancer (BC) despite high risk scoring on multigene sequencing analysis for OncotypeDX (ODX) or MammaPrint (MP), in which the survival benefit of chemotherapy is clear.
Patients and methods: Patients with HR+/HER2- BC and high risk scoring on ODX (score >26) or MP were selected from the National Cancer Database (2004-2017). Only those who refused to get chemotherapy despite their physician's recommendations were included. Univariate frequency and proportion statistics were used to describe the patient cohort. Bivariate Chi-square analysis evaluated the association between refusal of recommended chemotherapy and sociodemographic characteristics. Significant variables (P < .05) were included in a multivariable logistic regression model.
Results: N = 43,533 patients were included (88.7% ODX, 11.3% MP). A total of n = 4415 (10.1%) patients declined chemotherapy despite recommendation by the patient's primary oncologist. Age >70 (OR: 3.46, 95% CI: 2.96-4.04, P < .001), black race (OR: 1.20, 95% CI: 1.07-1.36, P = .01), non-private insurance, lobular carcinoma histology (OR: 1.21, 95% CI: 1.09-1.35, P < .001), and tumor grade of I significantly predicted chemotherapy decline.
Conclusion: Identifying and addressing many of the factors that contribute to under-treatment in minorities is to be key to reducing cancer disparity and improving equity in cancer care and outcome.
Keywords: Breast neoplasms; Chemotherapy; Decision making; Mammaprint; Oncotype dx; Registry analysis; Treatment refusal.
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