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Chemotherapy is one of the main treatments for cancer of unknown primary (CUP). Find out how you have it and the most common side effects.

What is chemotherapy?

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

Cancer of unknown primary is an advanced cancer and unfortunately, most cases can't be cured. The aim of treatment is generally to relieve symptoms. It can also control the cancer and improve quality of life.   

When you have it

You usually have chemotherapy every 3 weeks. Each treatment period is called a cycle.

You might have the chemotherapy drugs on the first day or first few days of each cycle, followed by a recovery period with no chemotherapy. Or you might have some chemotherapy drugs once a week for the first 2 weeks of each cycle.

You may have up to 6 cycles of treatment, but this will depend on:

  • what chemotherapy drugs you are having
  • how the cancer is responding to treatment
  • the side effects you're having

Chemotherapy drugs

We can’t tell you for sure which chemotherapy drugs you will have for cancer of unknown primary. This is because the range of drugs and combinations that doctors might use is so large.

Your doctor chooses drugs that they think will suit you best. This depends on:

  • the results of all your tests
  • the side effects of the drugs
  • your general health and fitness

You usually have a combination of 2 or 3 chemotherapy drugs. The most commonly used chemotherapy treatments include: 

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

You might have other types of chemotherapy if you have cancer spread in certain areas of the body, such as the lymph nodes of your 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. 

Your doctor may refer you to a team that specialises in cancers of the female sex organs (gynae oncology team). You might have a platinum chemotherapy such as cisplatin or carboplatin, alongside paclitaxel or docetaxel.  

This might suggest that the cancer has started in your head or neck. Your doctor will usually refer you to the head and neck specialist team for treatment. 

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

If you have cancer spread in the liver or lungs, doctors will use the results of all your tests to choose the best chemotherapy treatment for you. It might be:

  • epirubicin, cisplatin and capecitabine or fluorouracil
  • epirubicin, oxaliplatin and capecitabine
  • carboplatin and paclitaxel
  • gemcitabine

Cancer can sometimes develop in cells of the neuroendocrine system. 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 carboplatin and etoposide.

Once you know which drugs you are going to have, you can learn more about them in our section about cancer drugs. 

How you have it

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 newspapers, books or electronic devices to 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.

Before you start chemotherapy

COVID swab test

Due to coronavirus, you need to have a test to check for coronavirus before you have treatment. The test is called a COVID swab test.

To have the test your nurse takes a sample from the inside of your nose and the back of your throat. They use a long cotton bud to take the sample. Or the sample might be saliva or other fluid. Depending on which test your hospital uses, it can take from 90 minutes to a few days to get a result.

At most hospitals, you have a COVID swab test 48 to 72 hours (up to 3 days) before going for your treatment in the chemotherapy unit.

This means you might have the swab test on the same day that you visit the hospital for blood tests and your doctor’s clinic appointment. If you have treatment weekly or more often, some hospitals will ask you to have the swab test on the day of treatment.

Check with your team about when you’ll have the test as there are some differences between hospitals.

Blood tests

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, including 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.
Last reviewed: 
20 Nov 2017
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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.