Treatment options for cancer of unknown primary

The main treatment for cancer of unknown primary (CUP) is cancer drugs, most commonly chemotherapy. Other treatments you might have include:

  • radiotherapy
  • hormone treatment
  • surgery
  • treatment to help control symptoms

You may also have treatment as part of a clinical trial. 

Deciding which treatment you need

A team of doctors and other professionals discuss the best treatment and care for you. They are called a multidisciplinary team (MDT).

The treatment you have depends on:

  • where your cancer is
  • if it has spread to more than one area of the body
  • where your doctor thinks the cancer may have started
  • how abnormal the cells look under a microscope
  • your general health and level of fitness
  • your personal wishes

Your doctor will discuss your treatment, its benefits and the possible side effects with you.

Doctors can't cure most cases of CUP. This is because the cancer has already spread from one part of the body to another. But treatment can control it, relieve symptoms, and give you a good quality of life. Your doctor may also suggest holding off treatment for a while if you don't have many symptoms.

Finding out that your cancer can't be cured can be a big shock. It might help to talk to a close friend or relative about how you feel.

We're here for you if you or someone close to you has cancer. You can call our Cancer Research UK nurses on 0808 800 4040, from Monday to Friday, 9am to 5pm.


Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. The drugs circulate throughout the body in the bloodstream.

Chemotherapy is the main treatment for CUP. You often have a combination of 2 or 3 chemotherapy drugs.

Targeted cancer drugs

Treatment with targeted drugs might be available to you as part of a clinical trial.

Some trials use new techniques called molecular profiling to look for changes in the cancer cells. Doctors then targeted those changes with a targeted drug such as pembrolizumab.  

Molecular profiling isn’t routinely available on the NHS. Researchers need to find out more about how well these tests work.

Hormone treatment

Certain cancers have special proteins on the surface called hormone receptors. Doctors can look for these receptors by looking at a sample of cancer cells in the laboratory. 

Cancers that are most likely to have hormone receptors are breast, prostate and womb cancer. Your doctor might suggest you have hormone treatment if you have these receptors. This can help control the cancer.


Radiotherapy uses high energy rays to kill cancer cells. You might have radiotherapy:

  • to help treat symptoms caused by the cancer, such as breathing problems or pain. This is called palliative radiotherapy
  • after chemotherapy or surgery to try to control the cancer
  • to try to cure the cancer. For example, if you only have cancer in the lymph nodes in one area such as the neck

Depending on why you are having radiotherapy, you may have a single treatment or a course of treatments over several days or weeks.


Surgery is not often used to treat CUP. This is because:

  • the position of the primary cancer is not known
  • doctors can't usually remove all the secondary cancers

But doctors may offer it in particular circumstances.

Surgery to remove swollen (enlarged) lymph nodes in the head and neck area

If tests show that you might have cancer in the head and neck area, you usually have surgery to remove the affected lymph nodes and other nodes nearby. This type of surgery is called lymph node dissection. This can cure some people with CUP.

You often have radiotherapy to the area after this operation. This is to try to kill off any cancer cells that may have been left behind. Occasionally, you might also have radiotherapy to the area where your doctor thinks the primary cancer is most likely to be.

Surgery to help with symptoms

Your doctor may suggest surgery to relieve symptoms such as bleeding or blockages in the body caused by CUP. 

Clinical trials

Your doctor might suggest you take part in a clinical trial. Doctors and researchers do trials to make existing treatments better and develop new treatments.

Treatment to control symptoms

You might have other treatments to help control symptoms such as:

  • painkillers
  • anti sickness drugs
  • steroids

Your doctor might call this supportive or palliative care. You might have this in combination with the treatments mentioned above, or on its own.

Some people with advanced cancer might not be well enough to have certain treatments such as chemotherapy. Or they may choose not to have this kind of treatment. People can decide not to have treatment because of a number of reasons. For example, you may feel that the side effects of treatment outweigh the possible benefits.

Your medical team, including your specialist nurse, will support you. They can give you all the information you need to make decisions about treatment and answer any questions you have.

Your choices

Your doctor might offer you a choice of treatments. Discuss each treatment with them and ask how they can control any side effects. This helps you make the right decision for you. You also need to think about the other factors involved in each treatment, such as:

  • whether you need extra appointments
  • if you need more tests
  • the distance you need to travel to and from hospital

You might have to make further choices as your situation changes. It helps to find out as much as possible each time. You can stop a treatment whenever you want to if you find it too much to cope with.

If you decide not to have treatment

You may decide not to have cancer treatments, such as chemotherapy. But you can still have medicines to help control symptoms, such as sickness or pain.

Your doctor or nurse will explain what could help you. You can also ask them to refer you to a local symptom control team to give you support at home.

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