Impact of organized colorectal cancer screening programs on screening uptake and screening inequalities: A study of systematic- and patient-reliant programs in Canada

Background: Various provincial colorectal cancer screening programs have been implemented in Canada but have yet to be evaluated. Objective: We examined the effects of patient-reliant and systematic organized colorectal screening programs on colorectal cancer screening uptake and on screening inequalities by income, education, rural residence, and access to a primary care physician. Methods: Lifetime and recent (< 1,< 2 years) stool-based screening uptake were assessed among Canadian Community Health Survey respondents (cycles 2003-2014), aged 50-75 years, with no personal or family history of colorectal cancer. We used a difference-in-differences approach to estimate the effects of two systematic provincial programs (where all eligible residents receive screening kits via mail), and one patient-reliant program (where residents receive screening kits via mail following their request to a physician, phone line or website). Results: Overall, systematic and patient-reliant programs were associated with a 4- [95 % CI: 1%, 7%] and a 12-percentage point [95 % CI: 2%, 8%] increase in recent (< 2 years) stool-based screening, respectively, with effect sizes converging after three years at approximately 10 %. The patient-reliant program was associated with an 11 % [95 % CI: 5%, 17 %] increase in uptake among those with a physician, but no effect among those without-leading to increased inequality in uptake according to physician access. Interpretation: Both program types increase colorectal screening overall. Reliance on patients' request for screening may increase disparities according to physician access. Exploration of complementary targeted interventions in patient-reliant settings appears warranted.