Colorectal cancer

Also known as: bowel cancer, colon cancer, rectal cancer


Colorectal cancer develops when cells in the bowel tissue begin to divide and grow abnormally. More than 40,000 people in the UK are diagnosed with colorectal cancer every year.

What is colorectal cancer?

Colorectal cancer develops when cells in the bowel tissue begin to divide and grow abnormally. These cells can multiply and form tumours. 

When these tumours become malignant or cancerous, they can spread beyond the bowel to other parts of the body.

Colorectal cancer is also sometimes called colon cancer or rectal cancer, depending on where in the bowel the cancer starts. Colon cancer starts in the large bowel, which is part of your digestive system. 

The purpose of the large bowel (also known as the large intestine or colon) is to absorb water and salts from food and get rid of any waste products left over. 

Rectal cancer begins in the last part of the large bowel (rectum or back passage). This part of the bowel stores poo until it’s ready to be passed out of your body.

What are the causes of colorectal cancer?

Anyone can develop colorectal cancer, so the causes are not clear. But your chances of getting colorectal cancer may increase because of the following:


Older people are more likely to develop colorectal cancer, with the highest rates occurring in people over 80.

Family history 

Bowel cancer is more common in people with close family members who have had the illness, and particularly if these relatives were diagnosed before they were 50.


People with large numbers of polyps, which are benign growths, are more likely to develop colorectal cancer.

Inflammatory bowel disease 

People with chronic bowel inflammation from ulcerative colitis or Crohn's disease have an increased chance of developing colorectal cancer.


People who are overweight, smoke, drink too much alcohol, do not eat enough fibre, or eat a lot of red or processed meat have a higher chance of developing colorectal cancer.


The London Clinic offers screening tests for colorectal cancer, so we can check the health of your bowel and catch colorectal cancer early so we can treat it.

Research has found that people who have a routine flexible sigmoidoscopy between the ages of 55 and 64 reduce their chances of being diagnosed with advanced bowel cancer by around one third.

What are the signs and symptoms of colorectal cancer? 

The signs and symptoms of colorectal cancer can be subtle and easy to miss, particularly in the early stages of the illness. 

Signs and symptoms of colorectal cancer to look out for include:

  • Bleeding from your back passage or blood in your poo
  • A change from your normal bowel habit , such as your poo being looser or constipation
  • Not feeling hungry or a loss of appetite
  • Weight loss
  • Tiredness
  • Abdominal pain, which may get worse when you eat a meal
  • Bloating
  • A lump or swelling in your belly

An early diagnosis of colorectal cancer usually leads to better treatment results.

If you notice any unusual symptoms, please see a doctor or contact us at The London Clinic for screening tests.

How is colorectal cancer diagnosed? 

Thanks to our high-tech imaging equipment, dedicated endoscopy suite and expert pathologists, we accurately diagnose and stage colorectal tumours. 

Our first-class diagnostic service helps to ensure you get the best possible treatment. Here are the ways colorectal cancer is diagnosed:


A camera at the end of a long, thin, flexible tube is used to examine the full length of the inside of your bowel. A colonoscopy is currently the best way to check for bowel cancer and is performed by experts in our purpose-built endoscopy suite.

Pelvic MRI scan 

We have a state-of-the-art imaging department with specialists who are experts at creating and interpreting detailed MRI scans of inside your body.

Trans-rectal ultrasound scan (TRUS)

A small ultrasound probe is passed into the back passage to help get better images of the cancer.

Carcinoembryonic antigen (CEA) test 

Carcinoembryonic antigen is a protein produced by some types of cancer, and particularly bowel cancer. This blood test looks for high levels of CEA in your blood. 

However, high levels of CEA can be caused by smoking and non-cancerous conditions such as inflammatory bowel disease and liver disease, so a specialist may recommend further tests.

How is colorectal cancer treated?

Colorectal cancer treatment is an area in which The London Clinic excels. Our priority is to provide you with the very best and latest treatments, as well as outstanding personalised care.

The best treatment for your colorectal cancer will depend on the size and stage of the cancer and your age and general health. 

But surgery is usually the first line of treatment, and you may need further therapy to prevent colorectal cancer from spreading or coming back.


Surgery to treat colorectal cancer aims to remove the tumour, as well as part of the colon or rectum that it may be attached to. 

The extent of your surgery will depend on which part of your bowel is affected and how far your cancer has spread. If you have surgery for colorectal cancer, you may need to have a stoma. 

A stoma is an opening in the stomach that’s connected to the digestive system. It allows poo and other waste to leave your body and into a pouch. A stoma may be temporary or permanent, depending on the surgery you’ve had. 

At The London Clinic, our clinical nurse specialists will support you after your surgery and teach you how to manage your stoma and adapt to changes in your bowel habit. 


If you’re diagnosed with colorectal cancer, you may receive chemotherapy to kill cancer cells and reduce the risk of the cancer coming back. 

At The London Clinic, we have 22 first-class chemotherapy pods, which offer you privacy and exceptional comfort.


In our warm and welcoming Duchess of Devonshire Wing, we have a dedicated radiotherapy suite that features the very latest, state-of-the-art radiotherapy machines.

Our experts use the machines to precisely deliver high-energy x-ray radiation to colorectal tumours to destroy cancer cells and stop them from spreading. You’re more likely to be treated with radiotherapy if you have rectal cancer rather than colon cancer.

Radiotherapy may be used: 

Before surgery 

To shrink the cancer and increase the chances of complete removal.

Instead of surgery 

To cure or stop the spread of early-stage cancer, if you cannot have surgery.

As palliative radiotherapy

To control symptoms and slow the spread of cancer in advanced cases.

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