Age range 50-69 is right
I was very interested to read the results from the pilot sites for
colorectal cancer screening1 as I developed the original plans2 for this
service for the UK National Screening Committee (UKNSC) in 1996, which the
pilots have been testing.
The plans were based on the previous experience
of the three large trials 3-5, adapted for a general UK population, to
provide for a sustainable national programme. I estimated that an
additional 60,000 colonoscopies would be required for a bi-annual faecal-
occult blood testing (FOBT) programme offered to all those aged 50 to 69
years- hence the current initiative to develop endoscopy training before
any bowel screening programme can be implemented.
Most of my predictions
have proved to be accurate, but I underestimated the pathology which would
be found in patients recalled for colonoscopy following positive FOBT,
which has meant that the time allowed for each endoscopy has had to be
Part of my brief from the UKNSC was to justify the age range, which
has now been piloted. Participants in the Minnesota study3 were aged 50-80
whilst those in the Danish4 and Nottingham5 studies were 45-74. However,
colorectal cancer is rare in those under 50, with only 5% of cases
diagnosed, and these may have genetic implications. About 50% of cases
occur in the age range 50-69 6. In the Nottingham trial uptake at initial
invitation was significantly lower both in those aged 45-49, (only 37%)
and in those aged over 70 (48%) than in the 50-69 age group (55%). The
mortality benefit was divided into two age groups. It was 19% better for
those under 65 at the start of the study but only a non-significant 10%
better for those 65 or over, giving the quoted 15% overall figure. I
therefore recommended an age range of 50-69 based on these results and the
experience of the NHS Breast Screening Programme, where an age upper limit
of 64 had proved too low7.
The authors now suggest that we should go back to the Danish trial and
invite up to age 74, since the incidence continues to increase with age.
This argument ignores the natural history of colorectal cancer in the
context of an established national screening programme, which would
provide benefit by both primary and secondary prevention, through the
removal of precancerous lesions during colonoscopy as well as the
detection of invasive disease. As with screening for cervical cancer the
risk would be lower in those who had already been screened several times
before their 70th birthdays. The clinical and cost effectiveness of
continuing beyond this age would be decreased and it would be possible to
do more harm than good.
1. UK Colorectal Cancer Screening Pilot Group. Results of the first
round of a demonstration pilot of screening for colorectal cancer in the
United Kingdom. BMJ 2004;329:133-5.
2. Garvican L. Planning for a possible National Colorectal Cancer
Screening Programme. J Med Screen 1998;5:187-94.
3. Mandel JS, Bard JH, Church TR, Snover DC, Bradley GM, Schuman LM &
Ederer F for the Minnesota Colon Cancer Control Study. Reducing Mortality
from Colorectal Cancer by Screening for Faecal Occult Blood. N.Eng.J.Med.
4. Kronborg O, Fenger C, Olsen J, Jorgensen OD, Sandergaard O. Randomised
study of screening for colorectal cancer with faecal occult blood test.
5. Hardcastle JD, Camberlain JO, Robinson MHE, Moss SM, Amar SA, Balfour
TW, James PD, Mangham CM. Randomised controlled trial of faecal occult
blood screening for colorectal cancer. Lancet 1996;348:1472-7.
6. Lieberman D, Sleisenger MH. Is it time to recommend screening for
colorectal cancer? (Commentary) Lancet 1996;348:1463-4
7. Moss S, Brown J, Garvican L, Coleman DA, Johns L, Blanks RG et al.
Routine breast screening for women aged 65-69: Three year results from
evaluation of the demonstration sites. Br J Cancer 2001; 85:1289-94.
Competing interests: No competing interests