Cancer Incidence and Survival Among Ever-Incarcerated Patients in California and Massachusetts

Importance: Cancer is the leading cause of death in US prisons. Few studies have compared cancer incidence and survival for currently and formerly incarcerated populations with those for the general population.

Objective

To ascertain the association of prison incarceration with cancer outcomes, and to inform potential public health interventions. Design, setting, and participants: This cohort study used state cancer registry data on patients with cancer diagnosed in California and Massachusetts between January 1, 2010, and December 31, 2019. Identifiers of persons incarcerated in California and Massachusetts state prisons during this study period were linked to cancer registry data to identify incarceration status at diagnosis. Data analysis was performed between March 2023 and August 2025. Exposures: Current, former, or never incarceration status at diagnosis. Main outcomes and measures: Cancer incidence, which was calculated as standardized incidence ratios (SIRs) relative to never-incarcerated patients. Stage at diagnosis and survival outcomes were characterized. The association between incarceration status and diagnosis stage and survival were assessed using regression models adjusted for demographic characteristics, year of diagnosis, cancer type, and state of residence.