Colon (colorectal) cancer
Incidence
There are 32,000 new cases each year in the UK with men and women being equally affected.
Risk factors
Diet probably plays a major role but the evidence is weak for an increased risk associated with high fibre diet, meat, high sugar intake, alcohol and fats. The ingestion of vegetables has found to be protective possibly by altering the ability of anaerobic bacteria (which are found in excess in patients with colon cancer) to break down naturally occurring bile salts.
A history of inflammatory bowel disease especially ulcerative colitis or previous gall bladder removal can lead to bowel tumours but in the latter this increased risk only appears after 15 years.
Heredity
In approximately 8% of cases, there is an inherited risk. If there is a strong family history of bowel cancer before the age of 40 years of age, then the rest of the family should be screened for the common known gene mutations.
Prevention
A diet high in vegetables is recommended (other dietary changes are recommended in another section of the website). It is probably best to reduce intake of red meat and saturated fats.
If you have a family history of colon cancer then you should have a regular examination of the bowel (colonoscopy) especially if the age of onset was below 40 years.
In many parts of the country, the population is being offered colonoscopy screening and this will undoubtedly reduce the number of colon cancers that have spread and are incurable.
Symptoms and signs
Non specific symptoms such as weight loss or tiredness due to anaemia may be the first sign of bowel cancer. Others may develop colicky stomach pains, diarrhoea or blood in the motions
Treatment
This depends on how far the tumour has spread at the time of diagnosis. Ideally, the treatment of choice is surgery to try to remove the entire tumour. If this is not possible or there is a slight possibility that some cancer cells have been left behind, then chemotherapy is used after surgery in an attempt to eradicate any remaining tumour cells. In a few cases chemotherapy is given before surgery to reduce the size of the tumour in order to help the surgeon remove as much tumour as possible.