Bowel Cancer

Symptoms of bowel cancer

  • A lasting change in your bowel habit – going more often, looser motions or constipation.

  • Blood in your poo or bleeding from your back passage.

  • Pain or discomfort in your tummy area or back passage.

  • Trapped wind or fullness in your tummy.

  • A lump in your tummy area or rectum.

  • Feeling you have not emptied your bowel fully after going to the toilet.

  • Unexplained weight loss.

  • Feeling tired and breathless due to anaemia (fewer red blood cells).

All these symptoms can be caused by conditions other than cancer, but it’s important to go to the GP and get any unusual changes checked out, especially if they go on for more than 4–6 weeks. 

Can I be screened for bowel cancer?

Testing for bowel cancer when you have no symptoms is called screening. It can find polyps or early cancer. If cancer is found early, it can be treated and greatly improve your chances of survival. Bowel Screen, the National Bowel Screening Programme, offers screening to women and men aged 60 to 69 every two years. You collect a sample of your poo and send it off to be checked for blood. Blood doesn’t mean you have bowel cancer, but it can be a sign that you need more tests to check for cancer or other problems.

Diagnosing Bowel Cancer 

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

Your GP will refer you to the hospital if they think you need more tests. Other tests you might have include:


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.


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 or colonoscopy. These can be checked under the microscope to find out more about cancer if cancer cells are present in the sample.


When you are lying on your side, your doctor puts a long flexible tube into your back passage. This tube is called a colonoscopy. A light inside the tube helps your doctor to see any abnormal areas, polyps or swellings. 

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. 

Galway Clinic Colorectal Surgeons