Importance: Recent US guideline updates have advocated for colorectal cancer (CRC) screening to begin at age 45 years in average-risk adults, whereas Canadian screening programs continue to begin screening at age 50 years. Similarities in early-onset CRC rates in Canada and the US warrant discussion of earlier screening in Canada, but there is a lack of Canadian-specific modeling data to inform this.
Objective: To estimate the association of a lowered initiation age for CRC screening by biennial fecal immunochemical test (FIT) with CRC incidence, mortality, and health care system costs in Canada.
Design, setting, and participants/exposures: This economic evaluation computational study used microsimulation modeling via the OncoSim platform.
Main outcomes and measures: Modeled rates of CRC incidence, mortality, and health care costs in Canadian dollars.
Results: This analysis included 4 birth cohorts (1973-1977, 1978-1982, 1983-1987, and 1988-1992) representative of the Canadian population accounting for previously documented effects of increasing CRC incidence in younger birth cohorts. Screening initiation at age 45 years resulted in a net 12 188 fewer CRC cases, 5261 fewer CRC deaths, and an added 92 112 quality-adjusted life-years (QALYs) to the cohort population over a 40-year period relative to screening from age 50 years. Screening initiation at age 40 years yielded 18 135 fewer CRC cases, 7988 fewer CRC deaths, and 150 373 QALYs. The cost per QALY decreased with younger birth cohorts to a cost of $762 per QALY when Canadians born in 1988 to 1992 began screening at age 45 years or $2622 per QALY with screening initiation at age 40 years. Although costs associated with screening and resulting therapeutic interventions increased with earlier screening, the overall health care system cost of managing CRC decreased.
Conclusions and relevance: This economic evaluation study using microsimulation modeling found that earlier screening may reduce CRC disease burden and add life-years to the Canadian population at a modest cost. Guideline changes suggesting earlier CRC screening in Canada may be justified, but evaluation of the resulting effects on colonoscopy capacity is necessary.