The effect of numeric information about the likelihood of receiving a false negative or false positive result on people's attitudes towards colorectal cancer screening using faecal immunochemical testing (FIT).

Abstract

To examine the impact of numeric risk information about false negative (FN) and false positive (FP) rates in fecal immunochemical testing (FIT) on attitudes towards screening. 102 people aged 45-55, living in the UK, read 6 hypothetical vignettes presented online about the use of FIT kits to detect colorectal cancer, in which information about FN and FP rates was systematically varied. Numeric FN risk information reduced people's interest in screening, perception of screening effectiveness and lowered trust in screening compared to verbal FN information. Verbal FN information reduced perceptions of screening effectiveness and trust compared to no FN information. People with high subjective numeracy reported lower trust in screening following the provision of numeric FN information but numeracy did not moderate any other associations. FP information did not affect attitudes towards FIT testing. Numeric FN risk information decreased people's perceptions of screening effectiveness and trust in the results of screening. While it influenced people's interest in screening, the effect was small. Numeric FN information has a small effect on interest in screening and could promote informed decision making without affecting screening uptake.