ObeSity Related Colorectal Adenoma Risk

In the UK, around 1 in 16 men and 1 in 20 women will develop bowel cancer at some point in their lives. Most bowel cancers happen when a type of growth in the bowel called an adenoma eventually becomes cancerous. Cutting out adenomas reduces the risk of developing bowel cancer. Certain people are more likely to have adenomas than others, for example people who are overweight. People who are overweight are also more likely to develop liver disease by laying too much fat down in the liver. Studies in Asia have shown that people with fatty liver disease are more likely to have adenomas and these are more commonly found in the part of the bowel (right colon) furthest from the bottom end. Information on the link between obesity, fatty liver disease and adenomas is very limited, particularly in the Western population. The investigators will assess the link between body weight, fatty liver and adenomas in the UK population. 1430 patients will be invited; some through the bowel cancer screening programme and some with symptoms such as low blood count, bleeding or changed bowel habit. These patients will already have been referred for a camera test looking into the bowel, called a colonoscopy. Information including height, weight and some health questions will be taken. Blood samples will be taken. The investigators will compare the number of patients with adenomas who have liver disease or who are overweight with those who don't. This information will be used to develop a scoring system to predict risk of adenomas. This will help the investigators to decide if undertaking colonoscopies in these patients will identify those at increased risk of bowel cancer.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Aged 18 years and over
2. Able to give informed consent
3. Indications:

   1. Patients with positive faecal occult blood test (FOBt) referred for index colonoscopy as part of Bowel Cancer Screening Programme
   2. Colonoscopy conversion from Bowelscope
   3. Index diagnostic colonoscopy due to new gastrointestinal symptoms (including but not restricted to diarrhoea, change in bowel habit, abdominal pain, PR bleeding, weight loss), iron deficiency anaemia, family history of CRC, abnormal findings on cross sectional imaging

Exclusion Criteria:

1. Absolute contraindication to colonoscopy
2. Unable to give informed consent
3. Known colorectal cancer
4. Known polyposis syndrome
5. Previous total/subtotal colectomy
6. Known colonic stricture which would prevent completion of colonoscopy
7. Attending for therapeutic procedure
8. Attending for assessment of a known lesion
9. Attending for assessment of known inflammatory bowel disease (IBD)
10. Attending for surveillance colonoscopy (polyp surveillance, post colorectal cancer surveillance, IBD surveillance)
11. Colonoscopy within the last 5 years