Background Three large randomised trials have shown that screening for colorectal cancer (CRC) using the faecal occult blood test (FOBt) can reduce the mortality from this disease. The largest of these trials, conducted in Nottingham since 1981, randomised 152 850 individuals between the ages of 45 and 74 years to an intervention arm receiving biennial Haemoccult (FOB) test kit or to a control arm. In 2006, the National Bowel Cancer Screening Programme was launched in England using the FOBt, with the expectation that it will reduce CRC mortality.
Aims To compare the CRC mortality and incidence in the intervention arm with the control arm after long-term follow-up.
Methods The 152 850 randomised individuals were followed up through local health records and central flagging (Office for National Statistics).
Results At a median follow-up of 19.5 years there was a 13% reduction in CRC mortality (95% CI 3% to 22%) in the intervention arm despite an uptake at first invitation of approximately 57%. The CRC mortality reduction in those accepting the first screening test, adjusted for the rate of non-compliers, was 18%. There was no significant difference in mortality from causes other than CRC between the intervention and control arms. Despite removing 615 adenomas >10 mm in size from the intervention arm, there was no significant difference in CRC incidence between the two arms.
Conclusions Although the reduction in CRC mortality was sustained, further follow-up of the screened population has not shown a significant reduction in the CRC incidence. Moreover, despite the removal of many large adenomas there was no reduction in the incidence of invasive cancer which was independent of sex and site of the tumour.
- Faecal occult blood testing
- colorectal cancer
- abdominal surgery
- cancer susceptibility
- colon carcinogenesis
- clinical trials
- colorectal cancer screening
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Funding This study was supported by the Medical Research Council with several project grants from 1987 to 2009 for data collection and trial administration.
Competing interests None.
Patient consent This trial was conceived in 1985, when permission from participants in a trial was not required. Since, it would not be possible to go back over 20 years later and seek permission to report the results of the trial, particularly as over half of those individuals randomised to participate are now deceased, no consent was obtained.
Ethics approval This study was approved by the Nottingham Family Practitioner Committee and BMA Medical Ethics committee in 1985. The requirements for trial registration did not exist at the start of this trial. Similarly in 1985 when this trial was being developed there were no formal ethics committees in each region, hence ethical permission was sought from the local Family Practitioner Committee as these patients were identified in general practice and the trial was approved by the BMA ethics committee as these were deemed the most appropriate bodies at the time.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data in this paper can be obtained from the corresponding author.