What is rectal cancer?

The rectum is part of the large bowel, which is part of the digestive system. Rectal cancer is more common in older people. In the UK, almost 6 in 10 bowel cancer cases (58%) each year are diagnosed in people aged 70 and over.

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

Related Stories & Media

Understanding rectal cancer
23 Feb 2017
This booklet is about rectal cancer. It is for anyone who has been diagnosed with rectal cancer.

Symptoms of rectal cancer

Having one or more risk factors does not mean you will get rectal cancer. Also, having no risk factors does not mean you will not develop rectal cancer.

Some people start by seeing their GP after experiencing symptoms. But there are other ways you may be diagnosed:

  • 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 are worried about rectal cancer, we have more information about the risk factors and the signs and symptoms.

Causes of rectal cancer

Doctors do not know the exact causes of rectal cancer. But there are risk factors that can increase your chance of developing it.

Having one or more risk factors does not mean you will get rectal cancer. Also, having no risk factors does not mean you will not develop rectal cancer.

Diagnosis of rectal cancer

If you have symptoms, you usually begin by seeing your GP. If they think that your symptoms could be caused by cancer, you should see a specialist at the hospital within 14 days.

The first tests you may have at the hospital are:

  • Rectal examination

    A rectal examination is when your doctor feels for any lumps or swelling by putting a gloved finger into your back passage (rectum).

  • Blood test

    You usually have a blood test to check for low blood cells (anaemia) and to check liver and kidney function.

You may then have the following tests:

  • Colonoscopy

    A colonoscopy looks at the inside of the whole length of the large bowel using a thin, flexible tube with a tiny camera on the end of it (colonoscope). You may have a sedative to help you feel more relaxed and it usually only takes about an hour.

  • Virtual colonoscopy

    A virtual colonoscopy uses a CT scan to build up a 3D picture of your bowel. You may have this test instead of a colonoscopy, or if the colonoscopy did not give a clear enough picture.

  • Sigmoidoscopy

    A sigmoidoscopy looks at the inside of the rectum and the part of the colon closest to the rectum. It uses a thin tube with a camera on the end. This may be uncomfortable but is not usually painful.

Waiting for test results 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. These are to find out more about the cancer. The results help your doctors plan your treatment. You may also have some of these tests again during and after treatment:

  • 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. Your doctors may check it regularly to see how well your treatment is working.

  • 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 colon. It also depends on your general health and preferences. You can read overview of treatment options for rectal cancer here.

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.

  • Chemoradiation

    Chemoradiation is a combination of chemotherapy and radiotherapy. It may be given before or after surgery.

  • Targeted therapies

    Targeted therapies interfere with the way cancer cells grow. They are sometimes used on their own or in combination with chemotherapy.

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 changes after treatment. We have more information on leading a healthy lifestyle after treatment.

How we can help

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