Radiotherapy for CUP

Radiotherapy uses high-energy rays to treat disease. It can be given both externally and internally.

  • External radiotherapy uses a machine to aim high-energy x-rays at the affected area.
  • Internal radiotherapy involves having a radioactive substance placed inside the body.

Radiotherapy works by destroying cancer cells in the area that’s being treated. Normal cells can also be damaged by radiotherapy, which may cause side effects. Cancer cells cannot repair themselves after radiotherapy, but normal cells usually can.

You can be given radiotherapy for different reasons. Doctors can give radiotherapy to try and control the cancer. It may be used with other treatments, such as surgery or chemotherapy.

If the cancer has spread more widely, doctors may give you radiotherapy to help relieve symptoms, such as pain or breathlessness. This is called palliative treatment.

The type of radiotherapy you’re given will depend on your individual situation.

What is radiotherapy?

Radiotherapy uses high-energy rays, usually x-rays and similar rays (such as electrons), to treat disease. It destroys cancer cells in the area that’s treated.

Normal cells can also be damaged by radiotherapy. They can usually repair themselves, but cancer cells can’t.

Radiotherapy is carefully planned so that it avoids as much healthy tissue as possible. However, there will always be some healthy tissue that’s affected by the treatment and this will cause side effects.


Radiotherapy to control the cancer

Radiotherapy can help to shrink and control the cancer and relieve symptoms. If the cancer is in one area of lymph nodes, such as the neck, armpit or groin, you may have radiotherapy to try to cure the CUP. It may be given on its own or together with treatment, such as surgery. You will usually have this type of radiotherapy over a few weeks.


Palliative radiotherapy

If the cancer has spread more widely, you may have radiotherapy to relieve symptoms. This is called palliative radiotherapy. It is usually given as a shorter course of treatment that is less likely to cause side effects. Palliative radiotherapy can be used to treat the following symptoms:

  • Pain – Radiotherapy shrinks the cancer and relieves the pressure that’s causing the pain. It may take a few weeks before you feel the full effect of treatment. It can help relieve pain if the cancer has spread to the bones.
  • Breathlessness – Radiotherapy may relieve breathlessness if the cancer is affecting your lungs.
  • Difficulty swallowing – Radiotherapy can help with swallowing difficulties by shrinking a cancer that’s pressing on the gullet (oesophagus).
  • Bleeding – Radiotherapy may help to stop or reduce any bleeding that might be caused by a cancer in the bowel, cervix or womb.
  • Brain swelling – Radiotherapy can be used to treat a secondary cancer in the brain. It reduces swelling and can help to relieve symptoms.


How radiotherapy is given

Radiotherapy can be given in two ways.

External radiotherapy

This is the most common way of giving radiotherapy.

You normally have it as a series of short, daily (Monday to Friday) outpatient treatments in the radiotherapy department. It is given using equipment similar to a large x-ray machine.

Sometimes a single treatment is all that is needed, or you may have a course of treatment. Each treatment takes 10 to 15 minutes. Your doctor will discuss the treatment and possible side effects with you. We have more information about having external radiotherapy.

Internal radiotherapy (brachytherapy)

Brachytherapy involves having a radioactive substance placed close to, or into, the tumour. It gives a high dose of radiotherapy directly to the tumour but only a low dose to the surrounding area. The radioactive substance may be left in the body for only a short time, or it may be left there permanently. If it is left inside the body permanently, the radioactivity gradually fades away over a short time.

Some people will have both external and internal radiotherapy.

Internal radiotherapy isn’t commonly used to treat CUP. Your cancer specialist will explain more about internal radiotherapy if it is an option for you.


Planning your radiotherapy

Radiotherapy has to be carefully planned to make sure it’s as effective as possible. It’s planned by a cancer specialist (clinical oncologist) and it may take a few visits.

On your first visit to the radiotherapy department, you’ll be asked to have a CT scan or lie under a machine called a simulator, which takes x-rays of the area to be treated.

You may need some small marks made on your skin to help the radiographer (who gives you your treatment) position you accurately and to show where the rays will be directed. These marks must stay visible throughout your treatment, and permanent marks (like tiny tattoos) are usually used. These are extremely small, and will only be done with your permission. It may be a little uncomfortable while they are done.


Treatment sessions

At the beginning of each session of radiotherapy, the radiographer will position you carefully on the couch and make sure you are comfortable. During your treatment you’ll be alone in the room, but you can talk to the radiographer who will watch you from the next room. Radiotherapy is not painful, but you will have to lie still for a few minutes during the treatment.

Back to Radiotherapy explained

Who might I meet?

You will meet many different specialists before, during and after radiotherapy treatment.

After treatment

It can take time to recover from radiotherapy. Support is there if you have any problems.