Symptoms and diagnosis of bowel cancer

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Symptoms of bowel cancer

• Changes in your poo for no reason that last longer than 3 weeks, such as having constipation, diarrhoea or both.
• The feeling of not emptying your bowel completely after a bowel movement.
• Needing to poo more or less often than usual.
• Blood in your poo, which may look red or black.
• Bleeding from your bottom.
• Tummy pain.
• Feeling a lump anywhere in your tummy.
• Bloating.
• Losing weight for no reason.
• Feeling very tired for no reason.
• Breathlessness.

Not everyone will get every symptom, or get symptoms in any particular order.

If you notice any of these changes, always get them checked by your GP.  

These symptoms can be caused by conditions other than cancer, but it's important to listen to your body and get any changes checked. 

Can I be screened for bowel cancer?

Testing for bowel cancer when you have no symptoms is called screening. BowelScreen is the national bowel screening programme. Once you register, BowelScreen delivers a free home test kit to people aged 59 to 69 every two years. You send back a sample of your poo. The sample is tested for traces of blood. If there is blood in the sample it doesn’t mean that you have cancer, but you may be advised to have more tests. 

If cancer is found early, it can be treated and greatly improve your chances of survival.

We have more information on bowel cancer screening.

Diagnosing bowel cancer

Tests with your GP

Your family doctor (GP) will talk to you about your symptoms. He or she may do some tests. For example:

Rectal exam (DRE): Your doctor puts a gloved finger into your back passage to feel for any lumps or swelling. It may be a little uncomfortable but does not hurt.

Blood tests: Your doctor will take blood to see if you are anaemic. Also, he or she may check how well your liver and kidneys are working. 

Stool sample: Your doctor may ask for a sample of your poo (stool) to check for any hidden blood.

Tests at the hospital

If your doctor thinks your symptoms need to be investigated, you will have more tests. Tests that can help to diagnose bowel cancer include:

Proctoscopy
A short thin tube is passed into your back passage (rectum) while you are lying on your side. Air is then pumped in so the doctor can see the area more clearly.

Sigmoidoscopy
A longer tube is passed further up into your bowel. A light inside the tube helps your doctor to see any abnormal areas in the lower part of your large bowel. A sample of cells (biopsy) can also be taken during a sigmoidoscopy.

Colonoscopy
The doctor passes a thin tube with a light and camera into your bowel through your back passage while you are lying on your side. This tube is called a colonoscope. They can look for any abnormal areas, polyps or swellings, and they may also take photos and samples of your bowel. When you are lying on your side, your doctor puts a long flexible tube into your back passage. A small sample of cells (biopsy) can also be taken during colonoscopy.

CT colonography
This is a type of scan. You will lie on a table which moves through the CT scanning machine. This can produce a 3D picture of your bowel. 

Cancer Research UK has a very helpful video on this.