The effect of repeated invitations to prevalence screening on inequalities in the NHS Bowel Cancer Screening Programme


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Siu Hing Lo1, Christian von Wagner1, Julia Snowball2, Stephen Halloran2,3, Jane Wardle1
1University College London, London, UK, 2Bowel Cancer Screening Programme, Southern Hub, Royal Surrey County Hospital, Surrey, UK, 3University of Surrey, Surrey, UK

Background

The NHS Bowel Cancer Screening Programme (BCSP) invites all age-eligible adults for colorectal cancer screening using a Faecal Occult Blood (FOB) test every two years, irrespective of previous uptake. Existing research has shown that repeated invitations engage some previous non-responders, but it is unknown what effect continued offers of screening have on socioeconomic and gender inequalities in uptake and clinical outcomes.

Method

Data from the Southern BCSP Hub of all individuals (n= 62,099) aged 60-64 years at the time of first invitation to prevalence screening (September 2006 - February 2008) with a follow-up period of at least 4 years and 9 months were analysed. Of the 62,099, 23,677 received a second and 16,656 also received a third invitation to prevalence screening. The dataset included information on invitation dates, return dates if the FOB test had been completed, FOB positivity, colonoscopy or other follow-up test uptake, diagnostic outcomes, gender, age and an area-level measure of socioeconomic deprivation (IMD score).

Results

Uptake was 57% for the first, 23% for the second and 15% for the third invitation to prevalence screening, resulting in a cumulative uptake of 70%. Women were more likely to accept the first (OR= 1.39, 95% CI: 1.34-1.43) and second (OR= 1.09, 95% CI: 1.02-1.15) invitation, but less likely to accept the third invitation to prevalence screening (OR= 0.88, 95% CI: 0.81-0.96). More deprived invitees were less likely to accept any of the invitations to prevalence screening (results for IMD quintiles: 1st invitation: OR= 0.87, 95% CI: 0.86-0.88; 2nd: OR= 0.88, 95% CI: 0.86-0.90; 3rd: OR= 0.89, 95% CI: 0.86-0.92). Overall colonoscopy or other follow-up test attendance was very high, with few differences between socio-demographic groups.

FOB positivity rates were higher among individuals screened following their second (2.6%, p<.001) or third invitation (3.3%, p<.001) than for those screened following their first invitation (1.2%). Overall, cancer and adenoma detection rates were also higher among individuals screened after multiple prevalence screening invitations (result patterns differ per diagnostic outcome).

Conclusion

Repeat invitations are effective at increasing prevalence screening. They also reduce gender inequality, but the socioeconomic gradient remains stable across multiple invitation rounds for prevalence screening. Abnormal diagnostic outcomes are more common among individuals who delay prevalence screening.