Racial/ethnic differences in tumor biology and treatment outcomes in women with ductal carcinoma in situ

Background: Racial differences in invasive breast cancer exist, but less is known about ductal carcinoma in situ. Our aim was to assess racial/ethnic differences in ductal carcinoma in situ tumor biology and treatment. Methods: Adults with ductal carcinoma in situ were identified from the National Cancer Database, 2012–2021. Pairwise comparisons were evaluated among racial/ethnic groups with χ² or Wilcoxon tests. Multivariable logistic regression models evaluated outcome predictors for treatment and time to treatment. Results: Non-Hispanic Black patients had larger mean tumor size (2.2 cm, P ≤ .001). Non-Hispanic Black and Hispanic patients more frequently presented with multicentric disease (14.7% and 14.3%, P < .001). Non-Hispanic White patients had more grade III (45.1%, P < .01) and estrogen receptor–negative disease (14.2%, P < .04). On multivariable analysis, non-White race/ethnicity patients were less likely to undergo primary-site surgery (non-Hispanic Black odds ratio, 1.80; Hispanic odds ratio, 1.23; Asian/Pacific Islander odds ratio; 1.45, vs non-Hispanic White each P ≤ .002), as were uninsured and Medicaid-insured (uninsured odds ratio, 2.76; Medicaid odds ratio, 1.39; vs private insurance, both P < .002). Asian patients were more likely to undergo mastectomy (odds ratio, 1.08; 95% confidence interval, 1.02–1.15, P = .007), along with younger age (odds ratio, 0.64, P < .001), and multicentricity (hazard ratio, 2.23, P < .001). For breast conservation, radiation was less frequent among Hispanic patients (68.8%, P < .001). For estrogen receptor–positive ductal carcinoma in situ, non-Hispanic Black patients had the greatest receipt of endocrine therapy (61.9%%, P < .001) and Asian patients the lowest (56.9%, P < .001). On multivariable analysis, non-White race/ethnicity, uninsured, and Medicaid were associated with longer times from diagnosis to first surgery and from definitive surgery to radiation start. Conclusions: Racial/ethnic differences exist in ductal carcinoma in situ tumor biology and treatment, both of which may contribute to poorer outcomes in disparate groups.