Hormone therapy for cancer of unknown primary

Some cancers depend on hormones to grow. Hormone therapy works by either lowering the amount of hormones in the body or by blocking them from getting to cancer cells.

You might have hormone therapy if tests on the cancer show hormone receptors. There are a number of different types of hormone therapies. The type you need depends on a number of factors.

Hormone therapy isn’t a commonly used treatment for CUP.

What are hormones?

Hormones are substances that occur naturally in the body. They control the growth and activity of cells.

Some cancer cells have hormone receptors. Hormones can bind to these receptors and trigger the cancer to grow.

There are different types of hormones such as:

  • oestrogen
  • testosterone
  • progesterone

How does hormone therapy work?

Hormone treatments lower the levels of specific hormones in the body or block their effects. Different hormone therapies target different hormones.

Hormone therapy is only likely to work if the cancer of unknown primary (CUP) has hormone receptors. Your doctor checks your cancer cells for these receptors when you are diagnosed (from the biopsy sample). 

Cancers that have hormone receptors include:

  • breast cancer
  • prostate cancer
  • womb cancer
  • kidney cancer

Hormone therapy on its own doesn't cure CUP. But it can help to control the growth of the cancer, and relieve symptoms. Your doctor will talk to you about your treatment and why they have suggested hormone therapy.

Types of hormone therapy

There are different types of hormone therapy. The drug you might have depends on the type of hormone receptors found on the surface of your cancer cells. Some examples of hormone therapy include:

  • anastrozole (Arimidex)
  • letrozole (Femara)
  • goserelin (Zoladex)
  • leuprorelin (Prostap)
  • flutamide (Drogenil)
  • bicalutamide (Casodex)
  • tamoxifen

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

How you have hormone therapy

You usually have hormone therapy as tablets or injections. Your doctor or nurse will tell you more about this.

Taking your tablets

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

Speak to your pharmacist if you have problems swallowing the tablets.

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

You should take the right dose, no more or less.

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

Injection into your muscle

Some drugs are injected into a muscle (intramuscular injections), usually in your buttocks or upper thigh.

You might have stinging or a dull ache for a short time after this type of injection, but they don't usually hurt much.

Injections under the skin (subcutaneous)

The skin of the tummy (abdomen), thigh and upper arm are the most common areas for giving subcutaneous treatment. You may be able to give these injections yourself.

The video below shows you how to give an injection just under your skin (subcutaneously). It's important to wash your hands well before giving yourself an injection.

Side effects

Hormone therapy does not usually cause bad side effects. The side effects vary depending on the particular hormone therapy drug you have.

General side effects include:

  • tiredness
  • headaches
  • feeling sick (nausea)
  • joint and muscle pain
  • hot flushes

You can read about the most common side effects in men and women in our hormone therapy section.

Last reviewed: 
27 May 2021
Next review due: 
27 May 2024
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    Lippincott, Williams and Wilkins, 2015

  • Cancers of unknown primary site: ESMO clinical practice guidelines for diagnosis, treatment and follow up
    K Fizazi and others
    Annals of Oncology, 2015. Vol 26, Supplement 5

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