Racial Disparities in Breast Cancer Treatments and Adverse Events in the SEER-Medicare Data

SIMPLE SUMMARY: Breast cancer (BC) occurs more frequently in white (W) women than in African American (AA) women, but AA women die at a greater rate from BC than W women. Disparities exist in all aspects of the disease, from screening and early detection, to access to and completion of treatment. There are reports that adverse events from treatment also occur more frequently in AA patients. Here, we showed differences in treatments administered to AA women using the SEER-Medicare dataset. We found that AA women receive universally less treatment in every category of cancer and stage in the setting of the National Claims History database of Oncology practice providers. The drugs used to treat BC were relatively similar between the two races. Still, there were small differences in rates of administration of drugs that caused higher rates of side effects, which caused higher overall rates of adverse events in AA patients. The data suggest that the setting where AA patients receive care affects their treatment rate and adverse events. It is possible that higher rates of recorded adverse events result in lower rates of treatment or completion of treatment in AA women with BC. ABSTRACT: Despite lower incidence rates, African American (AA) patients have shorter survival from breast cancer (BC) than white (W) patients. Multiple factors contribute to decreased survival, including screening disparities, later presentation, and access to care. Disparities in adverse events (AEs) may contribute to delayed or incomplete treatment, earlier recurrence, and shortened survival. Here, we analyzed the SEER-Medicare dataset, which captures claims from a variety of venues, in order to determine whether the cancer care venues affect treatment and associated adverse events. We investigated a study population whose claims are included in the Outpatient files, consisting of hospital and healthcare facility venues, and a study population from the National Claims History (NCH) files, consisting of claims from physicians, office practices, and other non-institutional providers. We demonstrated statistically and substantively significant venue-specific differences in treatment rates, drugs administered, and AEs from treatments between AA and W patients. We showed that AA patients in the NCH dataset received lower rates of treatment, but patients in the Outpatient dataset received higher rates of treatment than W patients. The rates of recorded AEs per treatment were higher in the NCH setting than in the Outpatient setting in all patients. AEs were consistently higher in AA patients than in W patients. AA patients had higher comorbidity indices and were younger than W patients, but these variables did not appear to play roles in the AE differences. The frequency of specific anticancer drugs administered in cancer- and venue-specific circumstances and their associated AEs varied between AA and W patients. The higher AE rates were due to slightly higher frequencies in the administration of drugs with higher associated AE rates in AA patients than in W patients. Our investigations demonstrate significant differences in treatment rates and associated AEs between AA and W patients with BC, depending on the venues of care, likely contributing to differences in outcomes.