Barriers to Cancer Care Among People Experiencing Homelessness in Chicago.

People experiencing homelessness (PEH) face profound cancer disparities, with frequent late-stage diagnosis, lower treatment completion rates than housed populations, and up to twofold higher cancer mortality. In Chicago, where homelessness is shaped by structural racism, economic disinvestment, and healthcare resource deserts, PEH carries a concentrated burden of cancer risk. Factors including high tobacco and alcohol use, chronic viral infections (hepatitis C virus (HCV), hepatitis B virus (HBV), HIV, and human papillomavirus (HPV)), severe dental disease, malnutrition, and untreated mental illness and substance use disorders contribute to the overrepresentation of specific malignancies, most notably lung, head and neck, cervical, liver, colorectal, and breast cancers, which are often missed early due to limited access to preventive care and screening. This review highlights critical gaps across the cancer care continuum (the comprehensive framework describing cancer prevention, detection, diagnosis, treatment, and survivorship) and underscores Chicago's urgent need for targeted, low-barrier interventions. Mobile medical clinics represent a scalable and community-centered solution to deliver cancer risk assessment, screening, linkage to care, and patient navigation directly to PEH, offering a promising strategy to improve early detection, reduce cancer mortality, and advance cancer equity in Chicago.