Colonoscopy is the most effective way of screening for bowel cancer in the early stages when the disease is most treatable. The problem is that the procedure is invasive and uncomfortable and some people can be unwilling to have it.


As gastrointestinal specialists, we recognise that, no matter how effective it is, a colonoscopy cannot help to detect cancer if people won’t attend for screening.

That’s why it’s important to be aware that there are alternative ways of screening for bowel cancer.


Why bowel cancer screening is so important

Screening is vital because, in its early stages, there may be no signs or symptoms to indicate you have bowel cancer. Cancer of the colon is generally slow growing, developing from small growths called polyps in the large intestine and rectum.

These can take up to 10 years to become cancerous and symptoms often do not occur until the cancer has grown or spread, which is when it is harder to treat. The vast majority of bowel cancer caught in the earliest stages can be successfully treated, which is why screening is essential.


When to have bowel cancer screening

It is important to attend for bowel cancer screening if:

  • You are over the age of 50
  • You are experiencing any of the possible symptoms of bowel cancer (bleeding when you go for a poo, a persistent change in your bowel habits, unexplained tiredness or weight loss, abdominal pain or bloating brought on by eating)
  • You are at high risk (for example, you at risk of hereditary bowel cancers)
  • You are worried.

Screening is offered on the NHS to people over the age of 60 (50 in Scotland). This is because bowel cancer occurs most frequently in older people.

However, it can affect you at any age and private screening allows you to be tested for bowel cancer at any age.  It can provide peace of mind if you are worried and it can be carried out at a time that suits you. For this reason, it is an increasingly popular choice.


How colonoscopy works

During a colonoscopy, a doctor inserts a long, flexible tube (a colonoscope) into your bottom and passes it up into your colon. It has a light and a camera at one end that allows the doctor to look for polyps. These are growths that can form in your colon and rectum and which, over time, can become cancerous.

If a polyp is found it will be removed using a wire loop passed through the colonoscope. The procedure is painless although you may experience some bleeding afterwards. You will normally be sedated during a colonoscopy so you will need someone to drive you home after the procedure.


Colonoscopy alternatives

Other tests that can be used to screen for bowel cancer are:

  • The Faecal Immunochemical Test (FIT) – this test, which can be done at home and sent off for analysis at a laboratory, looks for blood in your stool, which can be a sign of bowel cancer. If traces of blood are found, you will be referred for further screening tests.
  • Faecal Occult Blood Test – this is similar to the FIT test but more than one stool sample is needed.
  • Sigmoidoscopy – a short flexible tube (a sigmoidoscope) is inserted into the rectum to look for polyps. It is similar to the colonoscopy but only checks the lower colon rather than the entire colon.

Whilst these tests can give indications on the presence of bowel cancer and bowel polyps, they are not as comprehensive an examination as the colonoscopy.


If you are concerned about your bowel health or have any symptoms that might indicate bowel cancer it is important to talk to a doctor or gastrointestinal specialist who can discuss the options more fully with you.

Screening is one of the most effective ways to safeguard your health and can provide peace of mind and help you to make empowered choices.

Our consultants are experienced gastroenterologists and colorectal surgeons with roles in the NHS and as part of GI Doctors, private practice.

We have various London locations for your convenience and our consultation fees can be found here.


Working with a specialist that can promptly diagnose and monitor your symptoms, will give you the best chance to get back to feeling your best.