Up to forty countries have implemented a colorectal cancer (CRC) screening programme. The Netherlands has started implementing CRC screening in 2014. In the Dutch programme, individuals aged 55-75 are invited for stool-based screening every two years, leading to as many as eleven screening rounds. This high number of screening rounds is necessary to guarantee high programme sensitivity for CRC and its precursor lesions.
Screening fatigue: a potential threat?
Due to the limited data on participation over multiple screening rounds, it is uncertain whether or not invitees of an 11-round screening programme will stay motivated to attend screening. Invitees may lose the motivation to participate because of a false perception of decreased CRC risk after several negative test outcomes. We denote this phenomenon by the term ‘screening fatigue’, leading to decreased participation. Screening fatigue may be a potential threat for FIT screening programmes since repeated testing is important to achieve reasonable sensitivity for CRC precursor lesions.
Study aim
To evaluate the potential impact of screening fatigue on long-term screening effectiveness.
Study design
Our Adenoma and Serrated pathway to Colorectal CAncer (ASCCA) model was set up to simulate the Dutch CRC screening programme. To fully evaluate the potential threat of screening fatigue, we considered several scenarios differing in participation pattern, number of negative screens after which screening fatigue occurs and decrease in participation rate due to screening fatigue.
Results
- Thirty years of screening is predicted to reduce CRC incidence with 39% and CRC mortality with 53% compared to no screening
- Screening fatigue considerably reduced screening effectiveness as shown in Figure 1
- If individuals would refrain from further screening after three negative screens, CRC incidence reduction decreased to 25% whereas CRC mortality reduction decreased to 34%
Figure 1. The black squares indicate the reduction in CRC mortality due to thirty years of screening without screening fatigue. The other symbols indicate the reduction in CRC mortality due to screening for different scenarios of screening fatigue. The Figure clearly shows that screening fatigue can seriously compromise screening effectiveness, especially when it occurs after 1 to 5 negative screens and participation decreases with 50% or individuals refrain from further screening.
Conclusion
Screening will substantially decrease CRC incidence and mortality. However, screening effectiveness can be seriously compromised if screening fatigue occurs. This warrants careful monitoring of individual screening behaviour and consideration of targeted invitation systems in individuals who have (repeatedly) missed screening rounds.