Bowel cancer

You may be worried about bowel cancer, have been recently diagnosed, or you may be thinking of someone you care about.

This page has information about bowel cancer symptoms, getting diagnosed, managing treatment and side effects, and how Maggie's can help.

What is bowel cancer?

Bowel cancer is cancer that starts in the large bowel (large intestine).

It starts when cells in the large bowel grow in an uncontrolled way and form a tumour.

It is sometimes called:

• colorectal cancer
• lower gastrointestinal (lower GI) cancer
• colon cancer – when it starts in the colon
• rectal cancer – when it starts in the rectum

Types of bowel cancer

The large bowel is made up of the colon and the rectum (back passage).

Colon cancer and rectal cancer are both types of bowel cancer.

These are split into sub-types depending on the cell the cancer starts in, including:

• adenocarcinoma
• carcinoid tumours
• gastrointestinal stromal tumours (GISTs)
• sarcomas
• lymphomas
• squamous cell tumours
• melanoma

Primary and secondary bowel cancer

Bowel cancer can be primary or secondary.

Primary bowel cancer is bowel cancer that has not spread beyond the large bowel.

Secondary bowel cancer is when the cancer has spread from the bowel to other parts of the body. 

This is sometimes called advanced bowel cancer, metastatic bowel cancer or stage 4 bowel cancer.

Related cancers

Anal cancer is a rare cancer that affects the bowel opening (anus). It is different from bowel cancer, and is often caused by the Human papilloma virus (HPV).

Small bowel cancer is a rare cancer that starts in the small bowel (small intestine). It is sometimes called upper gastrointestinal (upper GI) cancer.

Causes of bowel cancer

What causes bowel cancer is often unknown, but there are factors that may increase your risk of developing it.

Some of these risk factors are specific to bowel cancer, including:

• family history of bowel cancer
• type 2 diabetes
• Ashkenazi Jewish heritage
• exposure to radiation
• previous cancer
• polyps in the bowel, gallstones or acromegaly
• Helicobacter pylori (H. pylori) infection
• ulcerative colitis or Crohn's disease
• Lynch syndrome

Other risk factors are common to all cancers. Find out more about reducing your risk of cancer.

Having risk factors does not necessarily mean you will get bowel cancer. But it is helpful to be aware of the risks so you can see a doctor if you have any concerns.

Bowel cancer screening

People over 50 are most at risk of getting bowel cancer.

In the UK, everyone aged between 60–74 is sent an NHS bowel cancer screening kit every two years. Screening will be offered to people aged between 50–59 by April 2025.

You may be offered regular scans or blood tests if you have high-risk genetic factors or a family history of bowel cancer. Find out more about genetic testing for cancer.

Signs and symptoms of bowel cancer

Symptoms of bowel cancer often include changes to your bowel movements.

Sometimes, bowel cancer has no signs, but it can be detected early through screening.

When bowel cancer does cause symptoms, these may include:

• blood in your poo – this can make your poo look dark
  
• bleeding from your bottom – this can be bright red
• mucus in your poo
• a change in your bowel habits for a few weeks or more, such as diarrhoea, feeling constipated, pooing more or less often, or narrower poo
• the feeling of needing to poo but not being able to
• pain or a lump in your tummy or bottom
• fatigue 
• weight loss
• shortness of breath

Most people with these symptoms do not have bowel cancer. But if you do have symptoms, it is important to speak to your doctor. 

If it is cancer, it will be easier to treat if it has been detected early.

Getting diagnosed with bowel cancer

If you have been having symptoms of bowel cancer, the first step will usually be to see your GP.

What happens in your GP appointment

Your GP will ask you to describe your symptoms. Be as specific as you can to help your doctor understand what the problem might be.

It can feel embarrassing to talk about bowel movements, but your doctor is there to help.

You should also tell them about any previous bowel problems you have had, and if you have a family history of bowel cancer.

The doctor might:

• examine you by feeling your tummy (abdomen)
• examine you by putting a gloved finger inside your bottom (rectum) to check for any lumps or swelling – this is called a rectal exam
  
• arrange blood and stool (poo) tests
• ask to see you again
• arrange for you to see a specialist at the hospital

A rectal exam is usually painless, but it can feel uncomfortable. You can ask for a chaperone or bring someone for support if you would prefer.

If your GP hasn't referred you to the hospital and your symptoms continue or get worse, you should make another GP appointment.

Find out more about preparing for your GP appointment.

Sometimes healthcare professionals use different words when talking about the bowel. For example:

• 'stool' or 'faeces' means poo
• 'rectum' or 'back passage' means inside your bottom
• 'abdomen' means tummy

Always ask if your doctor or nurse says something that you don't understand.

Testing for bowel cancer

A gastroenterologist is a specialist in the digestive system which includes the bowel. 

To find the cause of your symptoms, the gastroenterologist may arrange further tests, such as:

• an ultrasound scan of your abdomen (tummy) and rectum (bottom)
  
• a CT scan or an MRI scan
• a colonoscopy – where a camera is used to look inside your large bowel
• a bowel scope (flexible sigmoidoscopy) – where a camera is used to look at the lower part of your large bowel
• a biopsy, where a tiny sample of your bowel tissue is removed and tested

After these tests and scans, you will be given an appointment to receive your results.

Waiting for appointments, tests and results can be a difficult time, and you might find that asking some questions and preparing for your results helps. Find out more about how Maggie's can help.

Understanding a bowel cancer diagnosis

The doctor will explain if you have bowel cancer in your results appointment, and whether you need further tests and scans to see if the cancer has spread.

It is normal to feel overwhelmed or in shock after hearing that you have bowel cancer, and you might have a lot of information to process.

Our cancer support specialists are here to listen, to help you understand what your diagnosis means, and to find the right support for you.

Find your nearest Maggie's to talk to us, or find out more about understanding a cancer diagnosis.

Treatment for bowel cancer

Treatment can be aimed at shrinking a tumour, removing the cancer completely, or controlling the symptoms that it causes. 

You might be offered a combination of treatments.

The treatments most commonly offered for bowel cancer are:

• surgery
• chemotherapy
• radiotherapy
• chemoradiotherapy
• targeted therapies or biological therapies
• immunotherapy
• clinical trials

Your cancer care team will work together to decide which treatment options could be best for you. Your doctor and specialist nurse will then discuss these with you.

You might want to get a second opinion before deciding on a treatment plan.

Making treatment decisions can feel daunting, and you might have lots of concerns or questions. Find out more about how Maggie's can support you.

Managing the effects of bowel cancer and treatment

A bowel cancer diagnosis can affect your life in many ways. You may be dealing with:

• symptoms and side effects of bowel cancer and treatment
• changes to your day-to-day life
• worries about money
• a range of feelings and emotions

Contact or visit your nearest Maggie's centre and together we will find the right support for you.

You can also explore our cancer support pages for more information.

After treatment for bowel cancer

When treatment ends, it can leave you with mixed feelings of relief and uncertainty.

For many people, bowel cancer is treated successfully. For some, it comes back or is diagnosed at an advanced stage from the start.

We have more information on finishing treatment and treatment for advanced cancer, as well as courses and workshops to support you and your family beyond treatment.

How Maggie's can help

We offer free expert psychological and practical support tailored to you, whatever stage you're at, and for friends and family too.

• Find your nearest centre to find out more, you can also leave your details and we’ll give you a call
• Just come in – you don't need an appointment

Last review: Nov 2024 | Next review: Nov 2027