Symptoms of bowel cancer

Symptoms of bowel cancer can include a change in your normal bowel habit or blood in your poo. They can also be symptoms for other conditions, but it’s important to see your doctor.

Bowel cancer can start in the large bowel (colon cancer) or back passage (rectal cancer). It is also called colorectal cancer. 

Possible symptoms of bowel cancer

The symptoms of bowel (colorectal) cancer can include:

  • bleeding from the back passage (rectum) or blood in your poo
  • a change in your normal bowel habit, such as looser poo, pooing more often or constipation
  • a lump that your doctor can feel in your back passage or tummy (abdomen), more commonly on the right side
  • a feeling of needing to strain in your back passage (as if you need to poo), even after opening your bowels
  • losing weight
  • pain in your abdomen or back passage
  • tiredness and breathlessness caused by a lower than normal level of red blood cells (anaemia)

Sometimes cancer can block the bowel. This is called a bowel obstruction. The symptoms include:

  • cramping pains in the abdomen
  • feeling bloated
  • constipation and being unable to pass wind
  • being sick

A bowel obstruction is an emergency. You should see your doctor quickly or go to A&E at your nearest hospital if you think you have a bowel obstruction.

Blood in your poo

Blood in your poo (stools or faeces) can be a sign of bowel cancer. But it is often due to other causes. See your GP if you are worried about any symptoms that you think could be caused by cancer in the bowel.

Most often, blood in the stool is from piles (haemorrhoids), especially if it is bright red, fresh blood. Piles are like swollen veins in the back passage. These veins are fragile and can easily get damaged when you have a poo, causing a little bleed. 

Blood from higher up in the bowel doesn't look bright red. It goes dark red or black and can make your poo look like tar. This type of bleeding can be a sign of cancer higher up the bowel. Or it could be from a bleeding stomach ulcer for example.

It is important to go to your doctor if you have any bleeding and get checked.

Your doctor won't think you are wasting their time. It’s very likely that you’ll have a rectal examination. This means the doctor puts a gloved finger into your back passage and feels for anything abnormal. 

Your doctor might send you to the hospital for further tests.

When to see your doctor

Go to see your GP if you are worried about any of the symptoms mentioned above.

Remember these symptoms can be caused by other conditions. Many of these are much less serious than cancer, such as piles (haemorrhoids), infections or inflammatory bowel disease. 

Last reviewed: 
03 Dec 2021
Next review due: 
03 Dec 2024
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