What is rectal cancer?

The rectum is part of the large bowel, which is part of the digestive system. In the UK, about 41,000 people get cancer in the large bowel each year.

We have more information about other types of bowel cancer including:

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Symptoms of rectal cancer

Some people may start by seeing their GP because they have symptoms. Symptoms of rectal cancer can include:

  • blood in your poo (stools)
  • bleeding from the back passage
  • a change in your normal bowel habit.

If you are worried about rectal cancer, we have more information about the symptoms.

Other people may be diagnosed by:

  • Having NHS Bowel Screening

    Bowel screening is a way of finding bowel cancer at an early stage before it causes symptoms.

  • Going to hospital with a problem, such as bowel obstruction

    This is when part of the bowel becomes blocked. It may cause symptoms such as tummy pain, nausea and vomiting, and constipation.

If you have any symptoms or notice anything that is unusual for you, you should see your GP straight away.

Causes of rectal cancer

The exact cause of colorectal cancer (colon or rectal cancer) is unknown. But, things called risk factors can increase the chance of a person developing it. Having one or more risk factors does not mean you will definitely get rectal cancer. And if you do not have any risk factors, it does not mean you will not get rectal cancer.

Diagnosis of rectal cancer

If you have symptoms, you will usually begin by seeing your GP, who will examine you. If they think that your symptoms could be caused by cancer, they will refer you to a specialist doctor.

At the hospital

The doctor will ask you about your general health and any previous medical problems you have had. They will also ask whether you have a family history of bowel cancer.

The doctor will examine you and you will usually also have one of the following tests:

  • Rectal examination

    A rectal examination is when the doctor places a gloved finger into your back passage to feel for any lumps or swelling.

  • Blood test

    You usually have a blood test to check your level of red blood cells. If you have a low number of red blood cells, this is called anaemia. You will also have blood tests to check if your liver and kidneys are working normally.

You may also have some of the following tests:

  • Colonoscopy

    A colonoscopy looks at the inside of the whole length of the large bowel. You can usually have this test as an outpatient. It takes about an hour.

  • Virtual colonoscopy

    In a virtual colonoscopy, a computerised tomography (CT) scanner takes a series of x-rays. This builds up a three-dimensional picture of your bowel.

  • Sigmoidoscopy

    A sigmoidoscopy looks at the inside of the rectum and the part of the colon closest to the rectum (the sigmoid colon). You can usually have it as an outpatient.

Waiting for tests can be a difficult time, we have more information that can help.

Further tests for rectal cancer

If any of your biopsies show that there is cancer in the rectum, you will have more tests. The results will help you and your doctor decide on the best treatment for you. Some tests may be repeated during and after treatment. You may have any of the following tests:

  • More blood tests

    Your blood may be tested for a protein called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein.

  • CT scan

    A CT (computerised tomography) scan uses x-rays to build a three-dimensional (3D) picture of the inside of the body.

  • MRI (magnetic resonance imaging) scan

    An MRI scan uses magnetism to build up a detailed picture of areas of your body.

  • Endorectal ultrasound scan (ERUS)

    An endorectal ultrasound scan (ERUS) can show the size and location of a cancer in the rectum, using sound waves to build up a picture. This test may be used to help plan your operation.

  • PET-CT scan

    A PET-CT scan is a combination of a CT scan, which takes a series of x-rays to build up a three-dimensional picture, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

Staging and grading of rectal cancer

The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.

A doctor decides the grade of the cancer by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.

Knowing the stage and grade helps your doctors plan the best treatment for you.

Treatment for rectal cancer

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

Surgery is the most common treatment for colon cancer. But the treatment you have depends on the stage of the cancer and where it is in the rectum. It also depends on your general health and preferences. Find out more about treatment options for rectal cancer.

Treatment may include:

  • Surgery

    Surgery is often used to remove cancer or areas affected by the cancer. It may also be used to help control symptoms

  • Chemotherapy

    Chemotherapy uses anti-cancer drugs to destroy cancer cells. You may have it before or after surgery. It may be given as as the main treatment if the cancer has spread.

  • Radiotherapy

    Radiotherapy is the use of high-energy rays, usually x-rays and similar rays (such as electrons) to treat cancer. It is sometimes given before surgery to shrink the cancer or it may be used to control symptoms.

  • Chemoradiation

    Chemoradiation is a combination of chemotherapy and radiotherapy. It is also sometimes called chemoradiotherapy.

  • Targeted therapies

    Targeted therapy drugs target something in or around a cancer cell that is helping it grow and survive. Targeted therapies are sometimes used to treat bowel cancers (colon or rectal) that have spread to other parts of the body.

You may also have some treatments as part of a clinical trial.

Most people have changes in how their bowel works after treatment for rectal cancer. These effects usually improve over time. We have more information about managing bowel changes caused by treatment.

After rectal cancer treatment

The aim of follow-up care is to make sure everything is going well and to find out if you have any concerns. The appointments are usually every few months in the first year.

We have more information on follow-up care after treatment.

Sex life

Rectal cancer and its treatment can affect your sex life. Changes may get better over time, but sometimes they are permanent. If you have any problems or are worried about this talk to your doctor or nurse. They can explain what to expect and there are often things that can help.


Some cancer treatments can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment. Making small changes such as eating well and keeping active can improve your health and well-being and help your body recover.

How we can help

Macmillan Grants

If you have cancer, you may be able to get a Macmillan Grant to help with the extra costs of cancer. Find out who can apply and how to access our grants.

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