Tests for cancer of unknown primary

You might have different tests to find out the cause of your symptoms. The tests you have depends on your symptoms. Sometimes, a cancer of unknown primary (CUP) is picked up on tests for something else.

If tests show you have cancer spread (secondary cancer), you usually have a number of further tests to try to find where the cancer started (the primary cancer).

We haven't listed all the tests you might have below. We have more information about tests to diagnose cancer and how you have them in our general cancer tests section.

You may not need all the tests below. 

Trying to find where cancer of unknown primary started

You have tests to try to find out where your cancer started (primary cancer). The tests you have depend on your symptoms. 

Biopsy for cancer of unknown primary (CUP)

A biopsy means taking a sample of tissue so that it can be looked at under a microscope. There are different types of biopsy. 

Blood tests for cancer of unknown primary

Blood tests can check your general health, for example, your blood cell levels and how well your liver and kidneys are working. Some blood tests can also help to diagnose cancer.

CT scan for cancer of unknown primary

A CT scan is a test that uses x-rays and a computer to create detailed pictures of the inside of your body. You might have one to look for the area where the cancer started and other areas where it might have spread to.

Ultrasound scan when you have cancer of unknown primary

An ultrasound scan can look for any abnormal areas in your tummy (abdomen) or pelvis. Find out how you have one.

PET-CT scan for cancer of unknown primary

You have a PET-CT scan to look for where a cancer started and areas of cancer spread. Find out what a PET- CT scan is, how you have it and what happens after it.

MRI scan for cancer of unknown primary

An MRI scan creates pictures using magnetism and radio waves. It can help to find out where the cancer started (primary cancer). 

Chest x-ray for cancer of unknown primary

You might a chest x-ray if you are having problems with your breathing. Find out about x-rays, including what they are and why you might have them.

Last reviewed: 
12 May 2021
Next review due: 
12 May 2024
Coronavirus and cancer

We know it’s a worrying time for people with cancer, we have information to help.

Read our information about coronavirus and cancer