Cancer Screening and Citizenship Status in the US.

IMPORTANCE: Immigrants without US citizenship, or noncitizens, disproportionately endure poverty, labor exclusions, and inadequate health care access-structural drivers of adverse cancer outcomes. While screening is critical for preventing cancer deaths, and cancer is the leading cause of death among noncitizens, little is known about citizenship status and its potential influence on cancer screening. OBJECTIVES: To examine cancer screening inequities associated with citizenship status, evaluate whether these inequities vary across states, and determine whether structural factors mediate these inequities. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used nationally representative data from the National Health Interview Survey (2010-2023). Eligibility for cancer screening and the timing and types of tests considered appropriate were determined using US Preventive Services Task Force guidelines. Data were analyzed from May to August 2025. EXPOSURE: Citizenship status: noncitizen (regardless of documentation), naturalized, or US-born. MAIN OUTCOMES AND MEASURES: Outcomes included colorectal, cervical, or breast cancer screening. Potential mediators included socioeconomic and health care factors (eg, poverty-to-income ratio and insurance), whereas clinical factors (eg, cancer history) were considered confounders. Mediation analysis using nonlinear multiple additive regression tree models was performed to evaluate associations between citizenship status and cancer screening and to identify mediators. RESULTS: The sample included 131 501 participants eligible for colorectal (3687 [5.1%] noncitizen, median [IQR] age, 61.1 [55.0 to 67.0] years, 39 040 [47.8%] male), cervical (6812 [10.2%] noncitizen, median [IQR] age 41.1 [30.0-52.0]), or breast (1815 [5.1%] noncitizen, median [IQR] age 60.8 [55.0-66.0]) cancer screening. In 2023, noncitizens had significantly lower colorectal (43.6%; 95% CI, 38.7%-48.4% vs 75.5%; 95% CI, 74.6%-76.5%), cervical (57.1%; 95% CI, 53.1%-61.0% vs 71.6%; 95% CI, 70.3%-72.8%), and breast (73.0%; 95% CI, 66.4%-78.7% vs 80.1%; 95% CI, 78.8%-81.3%) cancer screening rates than US-born citizens. These citizenship-based disparities were observed throughout the study period and were present in many states. Noncitizens had significantly lower odds of receiving colorectal (OR, 0.35; 95% CI, 0.32-0.38), cervical (OR, 0.41; 95% CI, 0.38-0.44), and breast (OR, 0.57; 95% CI, 0.52-0.62) cancer screenings than US-born citizens, with socioeconomic and health care factors jointly mediating these inequities (proportion mediated, colorectal cancer: 56.6%; 95% CI, 49.1%-64.2%; cervical cancer: 39.6%; 95% CI, 32.3%-47.0%; breast cancer: 97.1%; 95% CI, 87.1%-107.1%). CONCLUSIONS AND RELEVANCE: In this nationally representative study, noncitizens had lower rates of cancer screenings, an inequity largely explained by socioeconomic barriers and inadequate health care access. Efforts to increase cancer screening and reduce preventable cancer mortality among noncitizens should focus on improving their health care access.