Our summary
In the US, Black women have a higher incidence and mortality of metastatic breast cancer (mBC) compared to White women, while Hispanic women are reported to have lower rates. Few studies have focused on racial differences in treatment beyond their first treatment regimen and the subsequent impact on outcomes. This study aimed to investigate breast cancer treatment inequities across the care continuum for women with HR+HER2− mBC by examining differences in second-line treatment options and real-world overall survival (rwOS) across racial and ethnic groups. Researchers evaluated the use of cyclin-dependent kinase 4/6 inhibitor (CDKi), endocrine therapy (ET) and chemotherapy in second-line setting, and rwOS from second-line treatment initiation between race/ethnicity groups.
The study found that racial inequities in survival outcomes persist beyond the front-line setting, mainly among the subset of women who did not receive CDKi in their first line of therapy. Differences in treatment choices may be partially explained by tumor characteristics and socioeconomic status between race groups. Lack of uptake of CDKi earlier in the patient treatment journey may also be associated with racial inequities in breast cancer survival outcomes.
Why this matters
This is the first study comparing treatment choices beyond first-line and corresponding survival outcomes across race/ethnicity groups among patients in the second-line setting for HR+HER2− mBC. Evidence from randomized clinical trials suggests that compared to ET alone, combination of a CDKi and ET improved overall survival (OS) in both first- and second-line treatment settings. However, evidence on Black and Hispanic/Latino patients is limited in clinical trials. Therefore, real-world evidence among patients with mBC treated in routine practice may provide important insights on this topic.
Additionally, this research provides insight into treatment patterns in a patient cohort from community and academic practices, with a majority originating from community practices - representing a real-world population less represented in clinical trials. The findings, therefore, supplement current knowledge of real-world treatment patterns and outcomes among patients with HR+HER2− mBC by leveraging high quality contemporary electronic health record data and enable the assessment of longitudinal treatment patterns throughout the treatment journey for patients with mBC.