Cancer of unknown primary (CUP)

Having tests

Cancer of unknown primary (CUP)

Having tests

Not all symptoms are caused by cancer. Your GP or specialist will send you for tests to check what is causing your symptoms.

Your doctors should explain why you are having the tests and what they involve.

The number and types of tests performed will depend on how well the person is and how likely the test results are to affect treatment options. 

What you need to know

Tests for CUP

Initial tests

In most cases, your GP will examine you and send you for tests before you see a specialist. These initial tests are to see if your symptoms are caused by cancer or by something else.

In people with CUP, initial tests generally show there is cancer in the body but don’t show where the cancer started.

Further tests

Your GP will refer you to a specialist doctor who will arrange further tests.

The aim of the tests is to find the primary site of the cancer or identify the type of cells in the cancer so that suitable treatment can be started.

These tests can also help to work out which parts of the body the cancer has spread to. This information can be useful in assessing your response to treatment down the track and providing information about your prognosis.

The exact tests used will depend on your symptoms and what the initial test results showed.

Tests may include:

  • blood tests
  • medical imaging tests
  • endoscopy
  • biopsy.

Blood tests

Blood tests can measure different things, like the number of blood cells, or the amount of a substance in your blood. People with different cancers may need different tests.

You may have a blood test at your GP’s office, in a hospital, or at a special blood collection centre.

Medical imaging tests

Medical imaging is the name used for tests that produce pictures or images of the inside of the body. These include:

  • x-ray
  • CT scan
  • MRI scan
  • PET scan
  • ultrasound examinations.

You will need to go to a hospital radiology department or a private imaging centre to have these tests.  


In an endoscopy, a doctor looks inside part of the body, using an endoscope. This is an instrument with a light and a camera at one end and an eyepiece at the other. Many endoscopes have small tools that the doctor can use to take biopsies (samples) of the organs or tissues being looked at.

There are different types of endoscopy:

  • bronchoscopy
  • gastroscopy
  • colonoscopy
  • cystoscopy​
  • laparoscopy

Some endoscopies can be done in a doctor’s office but most will be done in a hospital or special clinic. You may be given sedation or an anaesthetic.

Biopsies for CUP

A biopsy is when a doctor removes a small piece of tissue from a lump or area that might be cancer. A pathologist then looks at this tissue under a microscope to see if it is definitely a cancer and what type of cancer it is. The pathologist then performs a series of tests to learn more about the cancer and where it may have started.

Sometimes, the pathologist may do further tests to help work out whether the cancer will respond to various treatments.

Biopsies may be taken from areas where your doctor thinks you may have cancer based on the initial test results. This can include areas such as swollen lymph nodes, the liver, bones or lungs.

Sometimes doctors will use imaging such as an ultrasound or CT scan to help guide where the tissue is taken from.  

There are different ways a doctor can get a biopsy. This can include:

  • fine needle aspiration
  • core biopsy
  • incisional biopsy
  • excision biopsy
  • biopsy taken during an endoscopy.

What to ask or talk about

Preparing for tests

Going for tests can make some people nervous, but knowing what to expect can help.

Your GP or specialist should tell you why you need each test and what it involves. Use our checklists to help you know what to ask.

Sometimes you need to contact the place where you are having the test for more information. This can include how to prepare for the test, how much it will cost and what you will get back from Medicare and your private health fund.

Ask how long it will take before you hear the results of the test.


Use our checklists to find helpful tips or questions to ask.

Next steps

Getting test results

It is normal to feel anxious when you are waiting for test results. 

Your GP or specialist should tell you when the results will be ready and how you will find out about them. Usually you need to make an appointment to get the results.

It is a good idea to take someone with you when you go for this appointment.

Possible CUP testing outcomes

There are several possible outcomes when a person has tests for CUP:

Test findings


The primary site of the cancer is found.

The person can be treated for that cancer type and no longer has CUP.

For example, if the tests show that the patient has cancer which has spread from the breast, they may go on to have treatments used for breast cancer, such as hormonal therapy or chemotherapy.

Cells in the cancer are identified as a type of cancer that can be treated without knowing the primary site, e.g. a sarcoma, melanoma or lymphoma.

The person can be treated for that cancer type and no longer has CUP.

For example, doctors often use immunotherapy to treat melanoma. It is not important to know exactly where the melanoma came from because this does not change the treatment.

The tests don’t identify a primary site or a type of cancer that can be treated without knowing the primary site.

The person has CUP and the specialist will discuss possible treatment options with them.

Where to get help

There are people you can talk to for more information or support.

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