Evelyn Wallace, Registered General Nurse and Cancer Care Clinical Manager

Bowel cancer symptoms and signs


25 March 2021

Evelyn Wallace, Cancer Care Clinical Manager, answers your most commonly asked questions about bowel cancer, colon cancer and rectal cancer.

What is bowel cancer?

Bowel cancer (also known as colorectal cancer) is an umbrella term given to a cancer that starts in the lining of the colon and rectum (or large bowel).

Most cancers of the bowel start with small, benign growths that develop in the lining of the gut. These can turn malignant over time if they aren’t treated. The cancer can then spread through the wall of the bowel. If it spreads further, commonly to the liver or lungs, it is very difficult to cure. If it is caught early when it is just in the bowel wall, the chances of cure are very good.

What are the symptoms of bowel cancer?

The main symptoms of bowel cancer are:

  • bleeding from your bottom and/or blood in your poo (please do look),
  • a change in bowel habit lasting for 3 weeks or more, especially to looser or runny poo,
  • unexplained weight loss or loss of appetite,
  • extreme tiredness for no obvious reason or shortness of breath,
  • a pain in your tummy,
  • or a lump in your tummy.

Tiredness and breathlessness may seem surprising but these can be symptoms of anaemia. Anaemia can occur due to loss of blood from a bowel tumour, so in that way it can be an initial symptom of bowel cancer.

You may get one, some or all of the above. None of these symptoms mean you have bowel cancer, but you should see your doctor to get them checked out.

The most important thing is to know what is normal for you, and if you notice any changes, see your doctor.

Who does bowel cancer most commonly affect?

Bowel cancer is one of the most common cancers in the UK.

Bowel cancer is more likely to develop in older people. The most common age group affected is 70-80. The NHS bowel cancer screening programme checks people aged  60 to 74, to  help detect bowel cancer at an early stage, when it's easier to treat. It can also be used to help check for and remove small growths in the bowel called polyps, which can turn into cancer over time.

Bowel cancer rarely occurs before the age of 50, but specialists always have it in the back of their minds, particularly if it runs in the family. If several members of your family have suffered from it then your risk of getting it is often higher.

The majority of bowel cancers do not have a genetic (or familial) cause. However a small number – perhaps 1 in 20 – do. In these cases, there are usually several close members (such as a parent, sister or brother) of the same family with bowel cancer. Also, the younger a person is when they get bowel cancer, the more likely it is to have a genetic cause. It can skip a generation, but this is unusual.

The key is to look out for any symptoms – see below for more details.

People with bowel conditions such as Crohn's disease and ulcerative colitis are more likely than the general population to develop bowel cancer because the bowel lining is inflamed. The risk of developing bowel cancer increases with the length of time the patient has had the disease.

This is why it is so important for individuals with these conditions to be seen regularly by a specialist so they can be monitored for early changes in the bowel lining which may lead to cancer.

How can you prevent bowel cancer?

There’s some evidence that a diet containing a lot of red and processed meats (such as smoked meat, ham, bacon, sausages, pâté and tinned meat) can increase the risk of developing cancer of the bowel. The greatest increase in risk seems to be for people who eat two or more portions of a day. Conversely, people who eat less than two portions a week seem to have the lowest risk.

Eating fried or grilled meat might also increase the risk. No link has been found between eating poultry (such as turkey and chicken) and an increased risk of bowel cancer.

A well balanced diet, high in fibre, is a good idea as evidence suggests that increasing fibre intake decreases the risk of colorectal cancer. Lots of fresh fruit, vegetables and unrefined grains, for example porridge, are good. Choosing brown rather than white bread is another good source of fibre.

Occasionally, you may be asked to follow a low fibre or low residue diet to rest your bowel, or as part of your preparation for surgery. These are specialised diets followed under the supervision of a dietitian.

You can also consider taking a child strength aspirin every day from age 50 as a preventative measure, but always take medical advice before starting this.

What is the bowel cancer screening process?

There is now an acceptance in the UK that bowel screening is important and can detect some bowel cancers at an early stage, though not all.

In the UK bowel screening is organised automatically. If you're aged between 60-74 in England and Wales, 60-71 in Northern Ireland and 50-74 in Scotland, you will receive your test kit through the post around the date of your birthday every two years.

If there is a strong family history of bowel cancer, earlier screening would be sensible. Strong family history means at least one close family member with bowel cancer at an early age.

There are two main stages of testing for bowel cancer.

  • The home screening test

This test looks for hidden blood in samples of your poo. It is an easy test to do and can be done in the privacy of your own bathroom. You just need to collect two smears of your poo on three different occasions. It is then sent off to a laboratory to be analysed.

You receive your results through the post within two weeks. If no blood is seen, you will be sent another kit in two years. Use the kit when you receive it, even if you have no signs of bowel cancer. The earlier a bowel cancer is detected, the easier it is to treat and the better the outcome.

If any blood is detected, you may have to repeat the test or be referred to see a specialist screening practitioner at a hospital. Here, a health history will be taken and you will be offered a colonoscopy.

  • A colonoscopy, or camera test

This involves passing a fibre optic endoscope through the anus to look along the colon. You are given a sedative for the test, so you are sleepy-but not knocked out. This investigation will be fully explained – including the necessary preparation – and you will have the opportunity to ask any questions.

There are risks associated with the procedure, but they are rare. The main risks are perforation of the bowel (1 in every 1000 colonoscopies) and the possibility of bleeding after the biopsy (when a small pinch of tissue is taken from the bowel lining). A colonoscopy will only be performed if your doctor thinks it is needed.

How is bowel cancer treated and what are the side effects?

There are many different types of treatment depending on the position of the tumour and how advanced it is (often referred to as ‘staging’).

In general, surgery, radiotherapy and chemotherapy can all be used.

If the cancer is detected early, many people will undergo surgery to remove the tumour. This alone can cure some patients, though not everyone is so lucky and the cancer can remain or return.

Radiotherapy isn’t often used for colon cancer, but it can be used in combination with chemotherapy – before or after surgery – on rectal cancer. This is to shrink the tumour to improve the chances of successful surgery, or reduce the invasiveness of the procedure.

Chemotherapy may be used after surgery just to make sure no cancerous cells are left behind. This is not really needed in stage 1 bowel cancer, but is likely for stage 2 and 3.

If the cancer has spread, your specialist will suggest further treatment. If it has moved to other vital organs, stage 4, palliative procedures can prolong life and provide relief, but t is unlikely that you will be cured. 

Side effects depend on the exact operation performed and which drugs are used for chemotherapy.

What are the chances of survival for bowel cancer?

The survival rates for all stages of bowel cancer have increased greatly in the last 10 or 20 years. New types of surgery, new ways of giving radiotherapy and new chemotherapy drugs have all been developed and all have contributed to improving the results.

Further reading

Coping with a cancer diagnosis AXA Health

Tried and tested, these practical tips can really help you manage the day-to-day challenges

How do I tell people I have cancer? – AXA Health

This can be a daunting part of the process, but it’s the perfect opportunity to reach out for the help and support you need.

5 cancer myths busted – AXA Health

Some useful tips to empower you as you navigate the new (to you) cancer journey.

Useful resources for help and support

NHS – Bowel / Anal cancer factsheet

Cancer Research UK

Bowel Cancer UK

Macmillan Cancer Support

Office for National Statistics – Cancer survival bulletins

Public Health England - Cancer survival index

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