What is cancer of unknown primary?

Find out what cancer of unknown primary is, how common it is and why a primary cancer might not be found.

Getting diagnosed with cancer of unknown primary

Most people are diagnosed with CUP after they become unwell and go to A&E. Others start by seeing their GP. Find out what to expect when you see a GP and tests you might have. 

Survival for cancer of unknown primary (CUP)

Survival depends on many different things such as the type and stage of cancer. No one can tell you exactly how long you will live.

Treatment for cancer of unknown primary

Treatment depends on a number of things, including where the cancer is and your general health. Cancer drugs such as chemotherapy are the main treatment for CUP.

Stages and types of cancer of unknown primary

There is no staging system for cancer of unknown primary (CUP). Doctors can group CUP by the type of cell the cancer started from. 

Research and clinical trials

Read about the latest research into cancer of unknown primary (CUP) and see how you can take part in a clinical trial.

Living with cancer of unknown primary

Advice and support are available to help you cope with cancer of unknown primary (CUP) and its treatment.

Risks and causes of CUP

Cancer of unknown primary (CUP) includes a variety of cancers. Find out why we can't be specific about the possible causes or risk factors of CUP.

Last reviewed: 
10 May 2021
Next review due: 
10 May 2024

Page Credits: 

This section has been written, reviewed and updated by Cancer Research UK’s Patient Information Web Team. Thanks to the expert medical professionals and people affected by cancer who have helped to review this information.

  • Dr Claire Mitchell (Consultant Medical Oncologist)
  • Our lay reviewers
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