Disparities in late-stage cancer diagnosis across a multi-site academic health system

Abstract Background Disparities in cancer stage at diagnosis persist despite the availability of screening for several common cancers. We evaluated demographic, clinical, insurance, and neighborhood-level factors associated with late-stage diagnosis in a multisite academic health system. Methods We conducted a retrospective cohort study of 26,698 adults diagnosed with breast, colorectal, or lung and bronchus cancer from 2015 to 2025 across six University of California academic medical centers. Late-stage disease was defined using structured TNM data corresponding to AJCC stage III or IV. Multivariable logistic regression assessed associations of patient characteristics, insurance coverage, comorbidity burden, and neighborhood context, measured using the Area Deprivation Index (ADI), Social Vulnerability Index (SVI), and Healthy Places Index (HPI), with late-stage diagnosis. We also tested for heterogeneity in the ADI association by cancer type. Results Late-stage disease was identified in 4,701 patients (17.6%). Compared with breast cancer, odds of late-stage diagnosis were higher for colorectal cancer (OR, 8.40; 95% CI, 7.62 to 9.27) and lung and bronchus cancer (OR, 14.24; 95% CI, 12.84 to 15.78). Relative to the least deprived ADI tertile, patients in moderately and highly deprived neighborhoods had higher adjusted odds of late-stage diagnosis (OR, 1.10; 95% CI, 1.01 to 1.20, and OR, 1.21; 95% CI, 1.10 to 1.33, respectively). Medicaid coverage and other or unknown insurance coverage were also associated with higher odds of late-stage disease. SVI was not associated with stage, and HPI did not reach statistical significance. The ADI association varied by cancer type ( P = .0001) and was observed only for breast cancer, for which high neighborhood deprivation was associated with 55% higher odds of late-stage disease (OR, 1.55; 95% CI, 1.31 to 1.85). Conclusion Late-stage cancer diagnosis was strongly associated with cancer type and was also associated with insurance coverage and neighborhood deprivation. The association between neighborhood deprivation and stage was confined to breast cancer, emphasizing the value of cancer-specific approaches to reducing disparities in late-stage diagnosis. Impact Health systems may use neighborhood measures and insurance information to identify populations who could benefit from targeted screening outreach, navigation, and interventions that reduce structural barriers to early cancer detection.