Chemotherapy for cancer of unknown primary

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

Cancer of unknown primary (CUP) is an advanced cancer. This means that unfortunately, it cannot be cured. The aim of treatment is generally to relieve symptoms rather than cure the cancer. It can also control the cancer and improve quality of life.   

When you have it

You usually have chemotherapy as cycles of treatment. This means that you have one chemotherapy drug or a combination of drugs then a rest to allow your body to recover. Each cycle of treatment varies depending on what you are having. But usually, it’s every 2 to 4 weeks.

When you have chemotherapy and for how long you have it depends on:

  • what chemotherapy drugs you are having
  • the aim of treatment. For example, if you are having chemotherapy to relieve symptoms or to try to cure your cancer
  • the side effects you're having
  • how the cancer is responding to treatment

Types of chemotherapy drugs

There are a number of chemotherapy drugs used to treat CUP. The type of drug you have depends on different factors such as:

  • the results of all your tests
  • the side effects of the drugs
  • your general health and fitness
  • whether you have other medical problems such as heart problems

Examples of chemotherapy for CUP include: 

  • carboplatin and paclitaxel
  • gemcitabine and carboplatin or cisplatin
  • epirubicin, cisplatin and capecitabine (ECX)
  • epirubicin, cisplatin and fluorouracil (ECF)
  • irinotecan and gemcitabine or oxaliplatin

You might have other types of chemotherapy if you have cancer spread that is similar to other types of cancer. For example, cancer spread to the lymph nodes of your armpit is considered similar to breast cancer. You may hear doctors call this a specific treatable syndrome. But most people with CUP do not have a specific treatable syndrome. Your doctor will always plan the best treatment for you.

Chemotherapy for cancer spread in the lymph nodes of the armpit

Your doctor may refer you to a breast cancer specialist if you have a type of cancer called adenocarcinoma in the lymph nodes of your armpit. This is because the cancer might have started in your breast.

You usually have a combination of chemotherapy drugs such as paclitaxel and doxorubicin. 

Chemotherapy for cancer spread in the layer of tissue around the tummy

This layer of tissue is called the peritoneum. If you have cancer cells in this layer of tissue your doctor may refer you to a team that specialises in cancers of the female sex organs. The team is called the gynae oncology team.

You might have a platinum drug alongside paclitaxel or docetaxel. Platinum drugs include cisplatin or carboplatin.

Chemotherapy for cancer spread in the area between the lungs or the back wall of the tummy

The area between your lungs is called the mediastinum. And the back wall of the tummy or abdomen is called the retroperitoneum. If you have cancer cells in either of these areas it might suggest that your cancer started in cells that make sperm in the testicles, or eggs in the ovaries. These are called extragonadal germ cell tumours Open a glossary item.

You usually have a combination of chemotherapy that includes the drugs cisplatin or carboplatin.  

Chemotherapy for cancer spread in the lymph nodes of the neck

This might suggest that the cancer started in your head and neck area. For example, it might have started in the tonsils. Your doctor will usually refer you to the head and neck team for treatment. 

You might have the chemotherapy drug cisplatin or carboplatin, alongside radiotherapy. This type of treatment is called chemoradiotherapy. 

Chemotherapy for cancer that might have started in the neuroendocrine system

Cancer can sometimes develop in cells of the neuroendocrine system Open a glossary item. If your doctor thinks you have this, they might refer you to a medical team that specialises in neuroendocrine tumours. 

You might have treatment with paclitaxel, carboplatin or etoposide. 

Check what is the name of the chemotherapy treatment with your doctor or nurse, then take a look at our A to Z list of cancer drugs.

How you have chemotherapy

You usually have chemotherapy through a drip into your bloodstream. Or you might take some chemotherapy drugs as tablets.

Into your bloodstream

You have the treatment through a drip into your arm or hand. A nurse puts a small tube (a cannula) into one of your veins and connects the drip to it.

You might need a central line. This is a long plastic tube that gives the drugs into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment, which may be for a few months.

Taking your tablets or capsules

You must take tablets and capsules according to the instructions your doctor or pharmacist gives you.

Whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream.

You should take the right dose, not more or less.

Talk to your specialist or advice line before you stop taking a cancer drug.

Where you have chemotherapy

You usually have treatment into your bloodstream at the cancer day clinic. You might sit in a chair for a few hours so it’s a good idea to take things in to do. For example, newspapers, books or electronic devices can all help to pass the time. You can usually bring a friend or family member with you.

You have some types of chemotherapy over several days. You might be able to have some drugs through a small portable pump that you take home.

For some types of chemotherapy you have to stay in a hospital ward. This could be overnight or for a couple of days.

Some hospitals may give certain chemotherapy treatments to you at home. Your doctor or nurse can tell you more about this.

Before you start chemotherapy

You need to have blood tests to make sure it’s safe to start treatment. You have these either a few days before or on the day you start treatment. You have blood tests before each round or cycle of treatment.

Side effects

Common chemotherapy side effects include:

  • feeling sick
  • loss of appetite
  • losing weight
  • feeling very tired
  • a lower resistance to infections
  • bleeding and bruising easily
  • diarrhoea or constipation
  • hair loss
Contact your doctor or nurse immediately if you have signs of infection. These include a temperature above 37.5C or below 36C, or generally feeling unwell. Infections can make you very unwell very quickly.

Side effects depend on:

  • which drugs you have
  • how much of each drug you have
  • how you react

Tell your treatment team about any side effects that you have.

Most side effects only last for a few days or so. Your treatment team can help to manage any side effects that you have.

When you go home

Chemotherapy can be difficult to cope with. Tell your doctor or nurse about any problems or side effects that you have. The nurse will give you telephone numbers to call if you have any problems at home. 

If you have any questions about chemotherapy, you can talk to Cancer Research UK's information nurses on freephone 0808 800 4040, 9am to 5pm, Monday to Friday.

Dietary or herbal supplements and chemotherapy

Let your doctors know if you:

  • take any supplements
  • have been prescribed anything by alternative or complementary therapy practitioners

It’s unclear how some nutritional or herbal supplements might interact with chemotherapy. They could be harmful.

Last reviewed: 
07 Jun 2021
Next review due: 
07 Jun 2024
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  • Cancers of unknown primary site: ESMO clinical practice guidelines for diagnosis, treatment and follow up
    K Fizazi and others
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  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact with details of the particular issue you are interested in.

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