Background: Structural racism – systems, structures, and institutions that perpetuate racial/ethnic inequities – influences cancer outcomes.
Objectives: To examine whether structural racism is associated with treatment initiation and survival among patients with four solid-tumor cancers – metastatic breast cancer (mBC), advanced non-small cell lung cancer (aNSCLC), metastatic pancreatic cancer (mPC), and advanced endometrial cancer (aEC).
Methods: This retrospective study used the US nationwide Flatiron Health electronic health record-derived de-identified database (2011-2022). Using data from the American Community Survey, we constructed a tract-level measure of structural racism – the Index of Concentration at the Extremes (ICE). ICE, which specifically measures racialized economic segregation, distinguishes between the most and least privileged populations in an area (i.e., high-income non-Latinx [NL]-White vs. low-income NL-Black households). ICE was categorized as population-weighted quintiles. To determine real-world treatment and survival, patients were followed from advanced/metastatic diagnosis to the event of interest, death, or last recorded activity. In disease-specific models, we examined the association of structural racism on treatment receipt (systemic therapy) and survival using Cox proportional hazards models adjusted for patient characteristics (age, sex, performance status, and disease stage).
Results: The cohort included 91,787 patients (mBC = 22,077; aNSCLC = 57,981; mPC = 8,347; aEC = 3,382) and had a median age of 69. Compared to patients from the most privileged areas, those from the least privileged area were younger (median age 67 vs. 70), disproportionately NL-Black (35% vs 2.5%) or Latinx (8.5% vs 1.9%), and had a worse performance status (ECOG ≥2: 12.0% vs 10.7%). Those in the least privileged areas (compared to the most privileged): had a longer time until treatment initiation for mBC (HR: 0.86, CI: 0.82-0.90), aNSCLC (HR: 0.86, CI: 0.84-0.89), and aEC (HR: 0.86, CI:0.76-0.98), but not mPC (HR: 0.92, CI:0.84-1.01); and had worse survival for mBC (HR: 1.21, CI: 1.14-1.28), mPC (HR: 1.09, CI: 1.00-1.18), and aEC (HR: 1.48, CI: 1.24-1.76), but not aNSCLC (HR: 0.99 CI: 0.96-1.02).
Conclusions: In these cancers with known and persistent health inequities, structural racism was associated with treatment initiation and survival in 3 out of 4 cancers. Efforts to reduce cancer inequities should assess and address the influence of structural injustices, including structural racism, on cancer care and outcomes.
