Purpose of Review <p>There are disparities in cancer incidence, mortality, and survival by race/ethnicity. As a result of structural mechanisms of discrimination, minoritized racial/ethnic groups are disproportionately exposed to higher levels of environmental carcinogens. Increased risk of exposure to harmful environmental pollutants may contribute to observed cancer disparities by race/ethnicity, but few studies have examined this effect. How race/ethnicity is operationalized in epidemiologic studies can impact interpretation of associations and potentially mask disparities, preventing the development of targeted public health interventions. We conducted a systematic review of epidemiologic studies on ambient environmental pollution and cancer outcomes in US adults and assessed how race/ethnicity was operationalized.</p> Recent Findings <p>A total of 3,346 studies were identified. We found that of 172 studies that included race/ethnicity, 85/172 (49%) only considered race/ethnicity as a confounder. Of the remaining 87 studies, 60/87 (69%) stratified analyses by race/ethnicity, 9/87 (10%) were minority health studies that included one non-White racial/ethnic group, 18/87 (21%) examined estimated cancer risk as an outcome with race/ethnicity as the main exposure. Despite these limited analyses, many of these studies found stronger associations among racial/ethnic minority groups. One study examined environmental exposures as a causal mediator to explain potential disparities in cancer outcomes.</p> Summary <p>There is a need for more research on racial/ethnic cancer disparities related to environmental pollutants. Researchers should consider developing data sources and leverage existing databases with robust racial/ethnic diversity and put ethical consideration into how race/ethnicity is included in conceptual frameworks to ensure fairness, equity, and clarity.</p>