Abstract
BACKGROUND: Historically, housing policies have perpetuated the marginalization and economic disinvestment of redlined neighborhoods. Residential segregation persists nowadays in the form of contemporary redlining, promoting healthcare disparities. The current study sought to assess the effect of redlining on oncological outcomes of patients with gastrointestinal cancer and identify mediators of the association. METHODS: Patients with colorectal or hepatobiliary cancer were identified from the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database (2007-2019). The contemporary redlining index, a measure of mortgage lending bias, was assessed relative to disease stage at diagnosis, receipt of appropriate treatment, textbook outcome, and mortality. Mediation analysis was used to identify socioeconomic, structural, and clinical mediating factors. RESULTS: Among 94,988 patients, 32.2% resided in high (n = 23,872) and highest (n = 6,791) redlining census tracts compared with 46.2% in neutral and 21.6% in low redlining tracts. The proportion of Black, Hispanic, and White patients experiencing high and highest redlining was 65.9%, 41.6%, and 27.9%, respectively. Highest redlining was associated with 18.2% higher odds of advanced disease at diagnosis, greater odds of not undergoing surgery for localized disease (adjusted odds ratio [aOR] 1.363, 95% confidence interval [CI] 1.219-1.524) or not receiving chemotherapy for advanced disease (aOR 1.385, 95% CI 1.216-1.577), and 26.7% lower odds of textbook outcome achievement. Mediation analysis for appropriate treatment quantified the proportion of the association driven by socioeconomic status, racial/ethnic minority status, racial/economic segregation, primary care shortage, and housing/transportation. CONCLUSIONS: Contemporary redlining contributed both directly, and via downstream factors, to disparities in oncological care and outcomes of patients with gastrointestinal cancer.