Routine screening for colorectal cancer is typically recommended until age 74 years. Although it has been proposed that screening stop age could be determined based on sex and comorbidity, less is known about the impact of screening history. We investigated the effects of screening history on selection of optimal age to stop screening.
We used the microsimulation model MISCAN-Colon to estimate harms and benefits of screening with biennial faecal immunochemical tests by sex, comorbidity status, and screening history. The optimal screening stop age was determined based on incremental number needed for 1 additional life-year per 1000 screened individuals compared to threshold provided by stopping screening at 76 years in the average-health population with perfect screening history (attended all required screening, diagnostic and follow-up tests) to biennial faecal immunochemical testing from age 50 years.
For persons of age 76 years, 157 women and 108 men with perfect screening history would need to be screened to gain 1 life-year per 1000 screened individuals. Previously unscreened women with no comorbid conditions and no history of screening could undergo an initial screening through 90 years, whereas unscreened males could undergo initial screening through 88 years, before this balance is reached. As screening adherence improved or as comorbidities increased, the optimal age to stop screening decreased to a point that, regardless of sex, individuals with severe comorbidities and perfect screening history should stop screening at age 66 years or younger.
Based on the harm-benefit balance, optimal stop age for colorectal cancer screening ranges from 66 years for unhealthy individuals with perfect screening history to 90 years for healthy individuals without prior screening. These findings can be used to assist patients and clinicians in making decisions about screening participation.

Copyright © 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.