What is radiotherapy?

Radiotherapy uses high energy rays to destroy cancer cells. Doctors use it in different situations to treat advanced prostate cancer.

It is most often used to shrink cancer that has spread to the bones. It is used to strengthen the bone and reduce pain. This helps you to keep you as active as possible without being in pain. Sometimes treatment to the bones may also help you live longer.

Radiotherapy can also help to relieve pain if the cancer is in a lymph node or pressing on the back passage (rectum). It can also help control bleeding in the urine (pee).

Radiotherapy to relieve your symptoms is called palliative radiotherapy.

Having radiotherapy for advanced prostate cancer

Radiotherapy to treat advanced prostate cancer can be given in two ways:

  • as external beam radiotherapy (see below) – where radiotherapy is given from outside the body (externally) from a radiotherapy machine
  • as an injection of a radioisotope (see below) liquid into a vein.

Your pain may get better within a couple of days of treatment, or it may take a couple of weeks for pain to improve. It may be up to 6 weeks before you feel the full benefit. Sometimes, the pain may get worse before it gets better.

You will need to keep taking painkillers during this time. Tell your cancer doctor or nurse if the pain gets worse, so they can increase your painkillers. When the treatment has worked, they can reduce them.

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External beam radiotherapy for advanced prostate cancer

You can have external beam radiotherapy as an outpatient in the radiotherapy department. Some people may need to stay in hospital while they have it. Radiotherapy is given using a machine that is like a big x-ray machine. This is called a linear accelerator (often called a LINAC).

You may have external beam radiotherapy as a single treatment or as a few sessions over a few weeks.

At the beginning of a treatment session (called a fraction), the radiographer will make sure you are in the correct position on the couch and that you are comfortable. Radiotherapy is not painful. But you have to lie still during the treatment. You may want to take your painkillers before you have it.

When everything is ready, the radiographer leaves the room so you can have radiotherapy. The treatment only takes a few minutes. You can talk to the radiographers through an intercom or signal to them during the treatment. They can see and hear you from the next room.

Your cancer doctor, nurse, or radiographer will explain your treatment and its possible side effects. They can give you advice to help you cope with any side effects. They can also help answer any questions you may have.

Side effects of palliative radiotherapy

The side effects of palliative radiotherapy are usually mild. They will depend on the area of the body that is being treated.

Tiredness (fatigue)

Feeling very tired is a common side effect. This should gradually improve a few weeks after treatment finishes. Try to pace yourself and get as much rest as you need. It helps to balance this with some gentle exercise, such as short walks, if possible.


You may feel sick if the area treated is close to your tummy, for example the ribs or spine. Your doctor can prescribe anti-sickness drugs to control any sickness.

If you only have 1 or 2 treatment sessions, you may have flu-like symptoms for a few days afterwards.

Always tell your nurse or radiographer about any side effects. There are usually ways to treat or manage them.

Spinal cord compression

If a tumour is close to or pressing on the spinal cord, it is called spinal cord compression. Doctors can treat this with a short course of external radiotherapy to the spine. You may have one single treatment or up to 2 weeks of radiotherapy.

Spinal cord compression causes symptoms, such as:

  • a new pain in your neck or back
  • numbness or pins and needles in your feet or hands
  • difficulty walking.

Spinal cord compression is not common, but it needs to be treated quickly to prevent permanent damage to the nerves. Always tell your doctor straight away if you have any of these symptoms.

Radioisotope therapy for advanced prostate cancer

Radioisotope therapy can be used to treat prostate cancer that has spread to the bones.

This treatment uses radioactive substances known as radioisotopes. Cancer cells absorb radioisotopes more than normal cells do. This means they get a higher dose of radiation to destroy them. All the bones affected by cancer will be treated. So, it can be very helpful if the cancer is in different areas of bone.

You may be given a radioisotope if hormonal therapy is no longer helping to control prostate cancer that has spread to the bone.

The radioisotopes that can be used are:

  • radium-223 (Xofigo®) – this is usually given once a month for 6 treatments
  • strontium-89 – this treatment can be repeated if you need it.

Having radioisotope therapy

Before radioisotope therapy, you have a blood test to make sure your blood cells are at a normal level. This is because radioisotopes can reduce the number of your blood cells.

You have the treatment as an outpatient in the radiotherapy department and go home on the same day. The hospital will give you information about this treatment.

The radiographer will give you the radioisotope as an injection into a vein in your arm. This only takes a few minutes. When they are finished, they cover the area with a small plaster.

After you have had the injection, you will have some radioisotopes in your poo (bowel movement), urine, and blood. Because of this, there are certain precautions you need to take when you go to the toilet. This is to protect yourself and others from being exposed to the radiation. You only need to do this for a week. For example, they will ask you to sit down to use the toilet rather than use a urinal. It is still safe for you to be with other people, including children. The hospital staff will explain more about this.

Side effects of radioisotope therapy

The side effects of radioisotope therapy are usually mild. You may have some diarrhoea or feel slightly sick. Your doctor can prescribe drugs to control these if needed.

The treatment can sometimes reduce the number of your blood cells for a short time. This is not usually a problem. But if you notice any unusual bruising or bleeding, contact the hospital straight away.

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    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editors, Dr Jim Barber, Consultant Clinical Oncologist and Dr Lisa Pickering, Consultant Medical Oncologist.

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