Symptoms and Diagnosis

In this section you can find out more about:

Remember, everyone is different and your symptoms and experience may not match those described below. If you have any further questions, be sure to ask your medical professional.


People with early stage bowel cancer often don’t display symptoms, so the disease goes unnoticed until it spreads to other parts of the body. However, some of the symptoms which can be apparent in the early stages are:

A consistent change in your bowel habits, including diarrhoea or constipation

  • Rectal bleeding or blood in your stool
  • Regular abdominal discomfort, such as cramps, gas or pain
  • A feeling that your bowel doesn't empty completely
  • Weakness or tiredness (fatigue)
  • Unexplained weight loss.

Many of these symptoms may have other causes, so it’s important to see your doctor if you experience any of these signs.

A Diagnosis of Bowel Cancer

A diagnosis of bowel cancer usually begins with a visit to your GP to check out your symptoms.

If your GP suspects bowel cancer, he or she may carry out a rectal exam and an abdominal exam. A number of other tests may also be done. These could include:

  • A Faecal Occult Blood Test (FOBT):
  • This is an analysis of a stool sample for the presence of blood.

  • Blood tests
  • These will measure the level of red blood cells in your blood (which can be low in people with bowel cancer) and the level of a protein known as CEA (which can be raised in people with bowel cancer).

  • A CT scan
  • This can give your doctor a good picture of your abdomen.

  • A colonoscopy
  • This is a procedure in which a small tube with a video camera is inserted down the entire length of the colon. If any polyps are found the surgeon can remove them at this time or take tissue samples of any larger more suspicious areas (a biopsy).

The Stages of Bowel Cancer

The results of your biopsy will be used to determine what stage of bowel cancer you have.

The staging of cancer is simply a way of determining how far the cancer has spread. There are five stages of bowel cancer and these are:



Stage 0

The cancer has not grown beyond the inner lining of the colon or rectum.

Stage I

The cancer has grown through the innermost lining of the colon or rectum, but hasn't spread beyond the colon wall or rectum.

Stage II

The cancer has grown into or through the wall of the colon or rectum, but hasn't spread to nearby lymph nodes.

Stage III

The cancer has spread to nearby lymph nodes, but hasn’t spread to other parts of the body.

Stage IV

The cancer has spread to other parts of your body, most often the liver. (Metastatic, advanced or secondary)

Your doctor will make treatment decisions based on the stage of cancer you have, the size and location of the tumour and your general health.