The English NHS Bowel Cancer Screening Programme (BCSP) offers biennial guaiac faecal occult blood testing (gFOBt) however there is a socioeconomic gradient in participation and socioeconomically disadvantaged groups have worse colorectal cancer survival than more advantaged groups.
We co-designed two simple, zero cost interventions aimed at reducing this gradient and improving uptake overall: a GP endorsement to the screening invitation, and an enhanced reminder letter.
We tested these interventions via cluster-randomised trials embedded in the screening programme:
- Trial 1 compared the standard invitation with general practice endorsement (GPE) of the programme on the invitation letter.
- Trial 2 compared the usual reminder letter with an enhanced reminder (ER) which included a banner reiterating the screening offer and a short paragraph restating the offer of screening in simple language.
- The primary outcome was the proportion of people adequately screened and its variation by deprivation (IMD).