Cancer incidence among incarcerated and formerly incarcerated individuals: A statewide retrospective cohort study

Background: Cancer incidence among individuals with incarceration exposure has been rarely studied due to the absence of linked datasets. This study examined cancer incidence during incarceration and postincarceration compared to the general population using a statewide linked cohort. Methods: We constructed a retrospective cohort from a linkage of state tumor registry and correctional system data for Connecticut residents from 2005 to 2016, and identified cancers diagnosed during and within 12 months postincarceration. We estimated incidence rates (including for screen-detectable cancers) and calculated the standardized incidence ratios (SIR) for the incarcerated and recently released populations, relative to the general population. We also examined cancer incidence by race and ethnicity within each group. Results: Cancer incidence was lower in incarcerated individuals (SIR = 0.64, 95% CI 0.56-0.72), but higher in recently released individuals (SIR = 1.34, 95% CI 1.23-1.47) compared with the general population, and across all race and ethnic strata. Similarly, nonscreen-detectable cancer incidence was lower in incarcerated and higher in recently released populations compared to the general population. However, non-Hispanic Black individuals had elevated incidence of screen-detectable cancers compared with non-Hispanic White individuals across all three populations (incarcerated, SIR = 1.66, 95% CI 1.03-2.53; recently released, SIR = 1.83, 95% CI 1.32-2.47; and general population, SIR = 1.18, 95% CI 1.16-1.21). Conclusion: Compared with the general population, incarcerated persons have a lower cancer incidence, whereas recently released persons have a higher cancer incidence. Irrespective of incarceration status, non-Hispanic Black individuals have a higher incidence of screen-detectable cancers compared with non-Hispanic White individuals. Supplemental studies examining cancer screening and diagnoses during incarceration are needed to discern the reasons for observed disparities in incidence.