- In theory, colorectal cancer is eminently amenable to screening because it has a prolonged premalignant phase.
- After the UK Colorectal Cancer Screening Pilot was completed, a national screening programme was due to be rolled out in April 2006.
- People aged 60-9 years will be performing faecal occult blood (FOB) tests at home every two years.
- The initial deadline for the screening programme of April 2006 could not be met because by this time no funding had been provided for the screening centres (BMJ 2006; 332: 742).
- The National Screening Committee estimates that the programme could save the lives of around 1,200 people a year in England alone.
This represents a reduction of about 9 per cent in the 13,000 annual death toll.
What is the evidence?
- Studies of most relevance for the UK were those carried out in Nottingham, England, and in Denmark, which showed reductions in deaths from colorectal cancer of 15 and 18 per cent, respectively, after screening (Lancet 1996; 348: 146, 1472).
- In a demonstration pilot, the UK Colorectal Cancer Screening Pilot Group used FOB testing to screen 478,250 people aged 50-69 living in England and Scotland (BMJ 2004; 329: 1,370).
They found that 57 per cent of those invited took part; 1.9 per cent had positive results, and the rate for detecting cancer was 1.62 per 1,000 people screened.
The cost of screening was about £5,900 per life.
A third of cancers tend to be missed if FOB is used alone for screening.
- Some experts say that since flexible sigmoidoscopy rather than colonoscopy should be considered.
However, an American study has found that this approach would miss two thirds of important lesions (N Engl J Med 2005; 352: 2061).
- Contacting people by telephone has been shown to improve attendance for screening from 39-63 per cent (Ann Int Med 2006; 144: 563).
Implications for practice
- Many GPs feel that screening for colorectal cancer will substantially increase their workload (BJGP 2005; 55: 20).
This came after most practice staff said that they spent less than 2 per cent of their time during the screening period on pilot-related activities.
- Assuming that 60 per cent of those offered screening take it up, the programme will generate an extra 30,000 colonoscopies in a service that is already overstretched.
www.cancerscreening.nhs.uk/bowel/pilot-evaluation.html - evaluation of the UK Colorectal Cancer Screening Pilot.
- Dr Louise Newson is a GP in the West Midlands and author of 'Hot Topics for MRCGP and General Practitioners', Pas Test 2006
- Colorectal cancer screening will be implemented in the near future.
- A screening programme will put even more pressure on endoscopy services.
- Many people will be anxious with false positive FOB tests.
- Screening is likely to increase GPs workload.