The many charities involved in increasing public awareness of bowel cancer achieve excellent results. The symptoms of bowel cancer are documented in simple terms, such as: bleeding from your bottom or blood in your poo, a change in bowel habit lasting for three weeks or more, unexplained weight loss or extreme tiredness for no obvious reason and severe abdominal pain. They also suggest that, if concerned about such symptoms, an appointment should be made with the GP. They, and the “Detect Cancer Early” and “Be Clear on Cancer” campaigns, emphasise that getting checked is not a waste of time, particularly because the earlier a bowel cancer is detected, the better the outcome.

However, there is much emphasis given to the view that people who have symptoms should be referred for the most reliable and accurate tests for diagnosing bowel cancer and, according to Cancer Research UK, for example, these are colonoscopy and flexible sigmoidoscopy. A recent report ‘Diagnosing bowel cancer early: right test, right time’ highlights well-known deficiencies with current endoscopy services all over the UK  – see:,-right-time/read-our-report/  The recommendations included that (1) urgent referral pathway for suspected bowel cancer should be liberalised so that GPs can refer a patient who has lower levels of risk than levels that currently apply and (2) greater investment in endoscopy services was needed to ensure future demand for services is adequately met.

Those who make such recommendations should be made aware of the Rule of Sixths. The extensive literature informs that, of the people being referred for lower gastrointestinal tract endoscopy from primary care;

1/6 have serious colorectal disease (colorectal cancer, advanced adenoma and inflammatory bowel disease,

2/6 have less serious bowel disease (diverticular disease, haemorrhoids, hyperplastic and small polyps), and

3/6 have no detectable abnormality on endoscopy.

So, how do we concentrate our scarce endoscopy resources on finding the 1/6 with serious colorectal diseases who would really benefit? Simple – instead of allocating large amounts of funding to endoscopy, encourage ubiquitous introduction of the measurement of faecal haemoglobin using FIT – faecal immunochemical tests for haemoglobin. There is now convincing evidence that these FIT are excellent tests in ruling in colorectal cancer when positive results are found – encouraging urgent referral for endoscopy. Perhaps more importantly, a negative result gives considerable reassurance that significant colorectal diseases is not present. Wide adoption of FIT, as either at point of care or, better, as an everywhere available laboratory test, would improve the current situation. Perhaps the bowel cancer charities need to refocus their efforts and support this inexpensive and evidence-based approach.

– Professor Callum G Fraser

Professor Callum G Fraser has worked in laboratory medicine in Scotland and Australia for 45 years. He has published 2 books, 12 book chapters and well over 300 papers, editorials and reviews. He has been involved with bowel screening since 1998, is Consultant to the Scottish Bowel Screening Research Unit, and is a Founding Member of the Expert Working Group on FIT for Screening, WEO.