Bowel cancer is also known as colon, rectal or colorectal cancer. The lining of the bowel is made of cells that are constantly being renewed. Sometimes these cells grow too quickly, forming a clump of cells known as a bowel polyp (sometimes known as an adenoma). Polyps are not bowel cancers (they are usually benign), but they can change into a malignant cancer over a number of years. A malignant cancer is when cancer cells have the ability to spread beyond the original site and into other parts of the body.
Bowel cancer is the third most common cancer in the UK, and the second leading cause of cancer deaths, with over 16,000 people dying from it each year.
The UK National Screening Committee (NSC) reviewed the evidence for bowel cancer screening, and found that population screening of people over the age of 50 for non-visible (occult) blood in faeces can reduce the mortality rate for bowel cancer. A pilot screening project was conducted across two pilot sites with very encouraging results. See the English Bowel Cancer Screening Pilot and Evaluation of English Bowel (Colorectal) Cancer Screening Pilot.
The NHS Bowel Cancer Screening Programme now offers screening every two years to all men and women aged 60 to 69 in England. The age range is currently being extended to 60 to 74 and is open to individuals opting-in to be screened from age 75 and above. People within the age range are automatically sent an invitation, then their screening kit, so they can perform the test at home. After the first screening test, individuals are sent an invitation and screening kit every two years. For further information about the NHS Bowel Cancer Screening Programme see www.cancerscreening.nhs.uk/bowel/index.html. Separate screening programmes are offered in Wales, Scotland, Northern Ireland and the Republic of Ireland.
Guidelines for bowel cancer screening in higher risk groups, for example, those with a significant family history, have been produced by The British Society of Gastroenterology.
On 28 April 2010 the Lancet published ‘Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial’. This paper was the culmination of over 10 years work inspired by UK academic Professor Wendy Atkin. In October 2010 the Prime Minister announced that flexible sigmoidoscopy would become a new screening modality for the national screening programme. Poor cancer survival rates in the UK relative to other European countries provided the backdrop to this initiative with the prospect that a once-only flexible sigmoidoscopy would save 3000 lives a year. The National Screening Committee approved this modality in April 2011. Since 2013, men and women living in 6 pilot sites have been invited to participate in “Bowel scope screening” around the time of their 55th birthday. The Bowel scope screening programme aspires to be fully rolled out to all 55 year olds by the end of 2016 and will function in addition to the existing NHS bowel cancer screening program.
The Screening Programme in England also intends moving the population-based screening from the current guaiac-based system (gFOBT) to a faecal immunochemical test (FIT). The immunochemical test is analytically superior, conferring increased analytical specificity for human haemoglobin, and through the use of sensitive detection systems, increasing test sensitivity to low blood concentrations. Instrumentation used for quantitative measurement also provides an opportunity to manually adjust the cut-off limit below which a test is reported as negative. FIT devices are currently being evaluated for the NHS by the Screening Hub in Guildford and a 6 month trial of FIT screening will commence in two areas in March 2014.