Colon cancer, also known as bowel cancer or colorectal cancer, is the third most common form of cancer.
Colon cancer is linked with diet factors and obesity and people with type 2 diabetes have been found to have a higher chance of developing it.
Colon cancer is most commonly diagnosed in older people as the risks increase with age.
What is colon cancer?
The colon is the large intestine which is the last part of the digestive system and ends at the rectum.
Colon cancer occurs when cells of the glands in the colon start to grow in an uncontrolled fashion, and therefore tumours develop.
If untreated, the cancer will grow into the muscle wall of the colon and can spread to neighbouring organs.
Risks of developing of bowel cancer
The risk of developing bowel cancer is increased for people who:
- Have a related bowel condition - such as Crohn’s disease or ulcerative colitis
- Have a close relative with bowel cancer
- Regularly eat processed meats
- Regularly drink alcohol
- Are overweight
The risk of bowel cancer increases with age.
Colon cancer and type 2 diabetes
People with type 2 diabetes have also been shown to be at a greater risk of developing bowel cancer although the reasons why are not yet understood well enough to say why.
Large scale research study published in 2011 indicated that people with type 2 diabetes had a 38% higher risk of developing colon cancer than those without diabetes.
Symptoms of colon cancer
The earliest stages of bowel cancer present no symptoms and so people are strongly encouraged to respond to bowel cancer screenings.
The sooner bowel cancer can be spotted, the easier it is to treat and the less chance it has to spread to neighbouring parts of the body.
Later stages of bowel cancer include:
- Blood in stools
- Constipation or diarrhoea that continues for more than 6 weeks
- Stomach or rectal pain
- Unexplained weight loss
Bleeding in the bowel can cause anaemia, which in turn can lead to persistent tiredness.
Diagnosis of colon cancer
Diagnosis of colon cancer involve your doctor feeling your abdomen for signs of the cancer. Your doctor will perform a rectal examination which will involve putting on a rubber glove and feeling inside your rectum.
This is normal procedure so don’t be too alarmed by the method of diagnosis.
Further tests may be needed such as sigmoidoscopy or colonoscopy, which examine the colon in more detail, to confirm presence of cancer.
Stages of colon cancer
Colon cancer will often be graded into stages, which helps to define the extent of treatment that is needed.
- Stage 1: if the cancer has not spread beyond the lining of the colon
- Stage 2: if the cancer has developed into the muscular layer around the colon
- Stage 3: if the cancer has developed into the lymph nodes
- Stage 4: if the cancer has spread into other organs of the body - advanced colon cancer
Treatment of bowel cancer
Treatment for colon cancer will depend on how far advanced the cancer is.
If the cancer is in stage 1, the cancer will often be treated with surgery alone to remove the cancer.
If the cancer is in stage 2 or 3, surgery can remove the cancer and chemotherapy will likely be given to prevent the cancer returning.
If in stage 4, the cancer cannot be eliminated but it may be possible to control the cancer using one of more of the following treatment options:
- Surgery - to physically remove the cancers
- Chemotherapy - medicines used to kill cancerous cells
- Radiotherapy - radiation in the form of high energy x-rays used to kill cancer cells
- Monoclonal antibody therapy - laboratory made antibodies which can target cancer cells and prevent them from spreading
Prevention of colon cancer
Red meats and, in particular, processed meats have been linked with increased risks of colon cancer and so the department of Health advises people to consume less than 70g (cooked weight) of red or processed meat.
Taking regular exercise and losing weight may also help to decrease your risk of developing colon cancer.
The NHS also advise quitting smoking to reduce the chances of developing bowel cancer as well as reducing risks of other cancers.