A discrete choice experiment to understand public preferences and priorities for risk-stratified bowel cancer screening programmes in the UK

Objective: Public acceptability of bowel cancer screening programmes must be maintained, including if risk stratification is introduced. We aimed to describe and quantify preferences for different attributes of riskstratified screening programmes amongst the UK population, focussing on who to invite for bowel screening. Methods: We conducted a discrete choice experiment (DCE) including the following attributes: risk factors used to estimate bowel cancer risk (age plus/minus sex, lifestyle factors and genetics); personalisation of risk feedback; risk stratification strategy plus resource implications; default screening in the case of no risk information; number of deaths prevented by screening; and number experiencing physical harm from screening. We used the results of conditional logit regression models to estimate the importance of each attribute, willingness to trade-off between the attributes, and preferences for different programmes using contemporary risk scores and models. Results: 1196 respondents completed the survey, generating 21,528 DCE observations. Deaths prevented was the most influential attribute on respondents' decision-making (contributing to 58.8% of the choice), followed by harms experienced (15.9%). For every three additional deaths prevented, respondents were willing to accept an additional screening harm per 100,000 people. Risk factors and risk stratification strategy contributed to just 11.1% and 3.6% of the choice, respectively. Although the influence on decision-making was small, respondents favoured more personalised feedback. Conclusions: Bowel cancer screening programmes that improve cancer outcomes, particularly by preventing more deaths amongst those screened, are most preferred by the public. Optimising risk prediction models, developing public communication, and readying infrastructure should be prioritised for implementation.