Rational targeting of population groups and residential areas for colorectal cancer screening

Sociodemographic and spatial disparities in incidence and mortality burden of colorectal cancer (CRC) are important to consider in the implementation of population screening, in order to achieve expected benefit and not increase health inequities. Analytic methods should be adapted to provide rational support for targeted interventions.

CRC incidence rates by tumor stage (I-IV) and location (colon vs. rectum) were analyzed for the time period 2008-2016 within a screening-relevant age interval of 55-74 years for the population of South and West Sweden, where screening is planned for. The study population was stratified by sex, country of birth, educational level (for Swedish-born citizens) and residential area. We also estimated disparities in excess mortality from CRC across groups of patients accordant to relevant population groups.

The analyses were based on 8961 patients with a first CRC diagnosis. There were marked socioeconomic gradients in the stage II-IV CRC incidence rates among Swedish-born men and women. Compared to men with high educational level, the incidence rate ratios (IRRs) of stage II, III, and IV CRC in men with low educational level were 1.38 (95% confidence interval 1.18, 1.62), 1.09 (0.95, 1.26), and 1.18 (1.02, 1.37), respectively. In women, the corresponding figures were 1.26 (1.06, 1.51), 1.19 (1.01, 1.39), and 1.45 (1.20, 1.80). The groups of patients with low educational level showed relatively high excess mortality burdens from CRC.

Our analytic approach provided rational support for targeted intervention when implementing CRC screening, aiming at optimizing participation in groups with low educational level.