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Radiotherapy for cancer of unknown primary (CUP)

Men and woman discussing unknown primary cancer

This page is about radiotherapy treatment for an unknown primary cancer. There is information about

 

A quick guide to what's on this page

Radiotherapy for cancer of unknown primary (CUP)

Radiotherapy uses high energy waves to treat cancer. Your doctor may recommend this type of treatment for certain situations if you have CUP.

How you have the treatment

Radiotherapy can be external or internal treatment. How you have the treatment depends on the part of your body being treated and whether the treatment is designed to help with symptoms or try to cure the cancer.

You usually have external radiotherapy as daily treatments from Monday to Friday, with a break at the weekend. The treatment can last from a few days to a few weeks. Sometimes you may have the treatment as a single dose. 

Internal radiotherapy is most commonly used if there are several areas of cancer cells in the bone. You usually have it as an injection. 

Side effects of radiotherapy

Apart from causing general tiredness, external radiotherapy causes side effects in the part of the body being treated. For example, radiotherapy to the neck can cause a sore throat and painful swallowing, whereas radiotherapy to the tummy (abdomen) tends to make you feel sick. 

Side effects tend to come on as you go through your course of treatment. If you have a short course you may have very few side effects. The side effects will gradually go in the days after your treatment has finished.

Internal radiotherapy tends to cause very few side effects but you may feel very tired for a few days.

 

CR PDF Icon You can view and print the quick guides for all the pages in the Treating CUP section.

 

 

What radiotherapy is

Radiotherapy uses high energy waves (radiation) to treat cancer. Your doctor may recommend this type of treatment in certain situations for cancer of unknown primary (CUP). 

Radiotherapy can be external or internal treatment. How you have the treatment depends on the part of your body being treated and whether the treatment is designed to help with symptoms or to try to cure the cancer. Your doctor carefully works out the total radiation dose. 

External radiotherapy beams pass through some body tissues and cause damage to body cells. But the radiotherapy tends to cause much more damage to cancer cells than it does to normal cells. So the cancer cells die but the healthy cells can recover. Internal radiotherapy is a mildly radioactive liquid that collects in the areas of cancer.

 

Planning external radiotherapy treatment

Before you begin your treatment, the radiotherapy team carefully plan your external beam radiotherapy. This means working out how much radiation you need to treat the cancer and exactly where you need it. Your planning appointment may take from 15 minutes up to a couple of hours. You will have a planning CT scan. The scan shows the cancer and the structures around it.

CT scanner

You lie on the scanner couch with the treatment area exposed. The radiographers will put some markers on your skin. You need to lie very still. Once you are in position the radiographers move the couch up and through the scanner. The scanner is a doughnut shape. 

The radiographers leave the room and the scan starts. It takes up to 5 minutes. You won't feel anything. The radiographers watch from the next door room.

Before the planning appointment you may also have other scans, such as MRI scans or PET scans. Your treatment team can feed the other scans into the planning scanner.

Ink marks

Once the treatment team has planned your radiotherapy, they may put ink marks on your skin to make sure they treat exactly the same area every day. They may also make pin point sized tattoo marks in these areas.

Moulds or masks

If you are having treatment to your head or neck, you may need to have a mould (shell) made to keep you perfectly still while you have treatment. You may also have a mould if you have to keep an arm or leg perfectly still.

After your planning session

You may have to wait a few days or up to 2 weeks before you start treatment. During this time the physicists and your radiotherapy doctor decide the final details of your plan. 

Your doctor will plan the areas that need treatment and outline areas to limit the dose to or avoid completely. They call this contouring. Then the physicists and staff called dosimetrists plan the treatment very precisely using advanced computers.

 

How you have external radiotherapy

Radiotherapy machines are very big. The machine may be fixed in one position or able to rotate around your body to give treatment from different directions. Before your first treatment your radiographers will explain what you will see and hear. The treatment rooms usually have docks for you to plug in music players. So you can listen to your own music.

You can't feel radiotherapy when you actually have the treatment. It takes anything from 10 to 25 minutes. It is important to lie in the same position each time, so the radiographers may take a little while to get you ready.

A photo of a linear accelerator, which gives radiotherapy

Once you are in the right position the staff leave you alone in the room for a few minutes. They watch you carefully on a closed circuit television screen.

Our page about having external radiotherapy has a video about having radiotherapy that you may want to watch.

External radiotherapy doesn't make you radioactive. It is perfectly safe to be with other people, including children, throughout your course of treatment.

 

Internal radiotherapy

Internal radiotherapy for CUP is most often used to treat a cancer that has spread quite widely through the bones. You usually have this treatment as an injection.

 

Radiotherapy for symptoms

Radiotherapy may be able to help if you have

  • Breathing problems
  • Bleeding
  • Bone problems
  • Swelling in an arm or leg

Breathing problems

Radiotherapy may be able to help if you have wheezing or breathlessness due to cancer cells in your lungs. 

Bleeding

Cancers can sometimes cause bleeding. This happens in some cancers that affect the skin. It can also happen with cancers in the back passage (rectum). Sometimes cancer cells in the lung can make you bring up small amounts of blood when you cough. You may hear this called haemoptysis (pronounced heem-op-tih-sis). Radiotherapy can sometimes reduce or stop the bleeding.

Bone problems

If your cancer was found because you had 1 or 2 secondary tumours in your bones, you are likely to be offered radiotherapy to the affected bones. The radiotherapy kills off the cancer cells in the affected bone and so shrinks the cancer. This helps to relieve pain. 

Once the cancer has been shrunk, the bone starts to heal itself by laying down more calcium and building itself back up again. This strengthens the bone.

For widespread cancer in the bone, specialists will sometimes suggest internal radiotherapy using a radioactive injection of strontium. The strontium in the injection travels through the body and is taken up by the bones. It can treat bone cancer throughout the whole body, whereas external radiotherapy is usually targeted at a particular bone or area of bones.

Swelling in an arm or leg

Fluid circulates around the body in the network of blood vessels and in the lymphatic system. Cancer can block the normal drainage routes and cause swelling. This swelling is called lymphoedema (lim-fo-dee-ma). It can happen either because a tumour puts pressure on blood vessels and lymphatic vessels. Or because cancer is growing in a lymph node (or group of lymph nodes). 

The lymph nodes normally filter the fluid that drains from body tissues. Cancer growing in a lymph node blocks this drainage route.

Radiotherapy may help to reduce swelling in either of these situations. How much it helps may depend on the primary type of cancer. Radiotherapy works better for some types of cancer than others.

 

Side effects of radiotherapy

Apart from causing general tiredness, external radiotherapy causes side effects only in the part of the body that is being treated. For example, radiotherapy to the neck can cause a sore throat and painful swallowing, whereas radiotherapy to the tummy (abdomen) tends to make you feel sick. 

The side effects tend to come on as you go through your course of treatment. If you have a short course of treatment of only a few days, you may have very few side effects. The side effects will gradually go in the days after your treatment has finished.

Internal radiotherapy tends to cause very few side effects but you may feel tired for a few days after the treatment.

 

More information about radiotherapy

Find out about

General radiotherapy

Internal radiotherapy 

Radiotherapy side effects

Radiotherapy skin markings

Radiotherapy moulds and masks

For general information and support

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Updated: 20 August 2014