Diagnosing cancer

What is cancer?

Cancer is a condition where cells in a specific part of the body grow and reproduce uncontrollably. The cancerous cells can invade and destroy surrounding healthy tissue, including organs like the brain or liver.

There are more than 200 different types of cancer, and each is diagnosed and treated in a particular way. Cancer sometimes begins in one part of the body before spreading to other areas.

Accurately diagnosing cancer can take several weeks. Many common cancer symptoms have other possible causes, and many people who are referred for further tests do not have cancer.

Cancer survival rates in England are higher than they have ever been, and earlier diagnosis usually leads to better outcomes. This is why it is important to act quickly if cancer is suspected, and why you should attend hospital appointments for tests when invited.

On this page you will find out about how cancer is diagnosed. There are links to useful videos, and other websites with more detailed information.


Need support now?

Macmillan support line 0808 808 0000 (8am-8pm, 7 days a week)

Use the Cancer Care Map to find support near you

What is cancer? (video with British Sign Language)

People you could meet

Your referral for suspected cancer

​When your GP suspects you might have cancer they will refer you to a specialist doctor at the hospital for further tests.

The hospital will contact you by telephone to book an appointment with a consultant, or for any tests that need to be done first.

This is called a fast track referral and your appointment will be booked within two weeks. If you do not hear back within one week of the referral please phone the hospital you have been referred to.

For more information about the process, and for contact details of the local hospitals, please visit our fast track referrals page.

Your fast track referral

It is very important that you attend your appointment at the hospital.

It might not be cancer that is causing your symptoms, but it is vital that we can either diagnose cancer or rule it out as quickly as possible.

If you have symptoms that are difficult to diagnose, but may suggest cancer, your GP can refer you to a new service called the Rapid Investigation Service for further tests. Click on the link to find more information about how this works and how you can contact them.

What to expect at your hospital appointment

Your first appointment might be with a consultant, or you may have a test or scan first. You will be told when someone from the hospital calls to book your appointment.

It might help to write down any questions you have for your consultant, and bring them with you to the appointment.

If you need to find out where to go and how to get there, visit our local hospitals page and follow the links to their websites for more information.

For more information about urgent referrals, and to help you prepare for your hospital appointment visit Cancer Research UK – Urgent Referral

If you are offered an appointment by video or phone call, you can watch this video about how you can make the most of a virtual consultation

COVID-19 update

Please check with the hospital to see if you can take someone with you. If it is possible, they may be asked to wait outside.

All hospitals are working hard to make sure it is safe to attend the hospital if you are advised to. Your test areas will be separated from areas where patients with COVID-19 are being treated. If you still feel unsure or concerned about attending hospital, please contact your GP.

Tests and diagnosis

How cancer is diagnosed

There are many types of cancer and they are diagnosed in different ways. The tests you need will be based on your exact symptoms.

In this section we describe some of the more common tests used for diagnosing cancer. You will find links to other websites where you can find more information about diagnosing specific cancer types. Here you can also find links to relevant videos in our library to show you what might happen during your hospital appointment.

CT scan

CT stands for computerised tomography. A CT scan, also known as a CAT scan, is a specialised X-ray test. It can give quite clear pictures of the inside of your body to give a more 3-dimensional view. In particular, it can give good pictures of soft tissues of the body which do not show on ordinary X-ray pictures. It will show possible cancer, its size and whether it has spread.

You can read more about what is involved in having a CT scan on the Cancer Research UK website.

You can also watch these videos from our cancer information library:

What is a CT scan?

Having a CT scan of your chest, abdomen and pelvis with contrast

MRI Scan

MRI stands for magnetic resonance imaging. An MRI is a type of scan that creates pictures using magnetism and radio waves. MRI scans produce pictures from angles all around the body and shows up soft tissues very clearly.

They take between 15 and 90 minutes.

You can read more about what is involved in having a MRI scan on the Cancer Research UK website.

You can also watch this video from our cancer information library:

An introduction to having an MRI scan


If you need a biopsy then a doctor will remove a small sample of your body tissue from the affected area, using a needle. This will then be examined under a microscope to find out whether you have cancer or not.

Sometimes biopsies may need to be repeated to get a more accurate diagnosis.

Your doctor or nurse will explain how the biopsy will be taken, and how long you will need to be at the hospital. It will depend on which part of your body the sample is taken from.

For more information about what to expect if you need a biopsy, visit Macmillan Cancer Support – Biopsy


An x-ray is a test that uses small doses of radiation to take pictures of the inside of your body. They are a good way to look at bones and can show changes caused by cancer or other medical conditions. X-rays can also show changes in other organs, such as the lungs.

You have x-rays in the imaging department of the hospital, taken by a radiographer

You can find more information about x-rays on the Cancer Research UK website.

PET Scan

PET stands for Positron Emission Tomography. The PET scan uses a mildly radioactive drug to show up areas of your body where cells are more active than normal. It is used to help diagnose cancer and can also help to find out whether cancer has spread to other parts of the body.

You can find more information about PET scans on the Cancer Research UK website. This includes a short video about what it is like to have a PET scan.


An endoscopy is a test that looks inside the body using an instrument called an endoscope.

An endoscope is a thin, flexible tube. The tube has a light and a camera at the end. It is passed into the body to help doctors see inside.

An endoscopy may also be used to remove a small sample of tissue from inside the body (a biopsy).

For more information about what to expect if you need an endoscopy visit Macmillan Cancer Support – Endoscopy

You can also watch this video in our cancer information library:

Having an Endoscopy

Other tests for cancer

There are many ways to test for different types of cancer. If you have been referred for a test that is not included here you can find more on these websites:

Cancer Research UK – Tests and scans

Macmillan Cancer Support – Diagnostic tests

Your test results

Your test results

Waiting for results can be stressful so it might help to talk to someone about how you are feeling.

Depending on the type of test it can take a few weeks to get the results.

You might receive a letter or phone call to tell you the results, or you will be invited for an appointment with a consultant or clinical nurse specialist. This should be made clear to you when you have the tests, so if you are not sure please ask.

If you do not have cancer, you may need further tests to diagnose something else.

If you are told you do have cancer, you will then be told what happens next. This could include further tests to assess the size of the cancer, or another appointment to start discussing your treatment options.

For more information about what to expect following a diagnosis of cancer, visit our cancer treatment and follow-up care page.


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