Radiotherapy for cancer of unknown primary

Radiotherapy uses high energy x-rays to treat cancer cells. External radiotherapy uses a radiotherapy machine to aim radiation beams at the cancer.

You have this treatment in the hospital radiotherapy department. It doesn't hurt, although laying on the radiotherapy couch can be uncomfortable.

Why you might have radiotherapy for CUP

Most people with CUP have radiotherapy to help control symptoms caused by the cancer, such as pain or breathing problems. This is called palliative treatment.

In some cases, you might have radiotherapy to try to cure the cancer. For example, if you have cancer spread in the lymph nodes in the neck. You may have the radiotherapy on its own or after surgery. 

You might have it as a one off treatment if you are having it to control symptoms. Or you might have it as a course of treatments over a number of weeks if you are having it to try to cure the cancer.

Your doctor will talk to you about why they are suggesting you have radiotherapy and what the aim of treatment is.

Planning your treatment

You have a planning session with your radiotherapy team a few days or weeks before you start treatment. This means working out the dose of radiotherapy you need and exactly where you need it.

Your planning appointment takes from 15 minutes to 2 hours.

You usually have a planning CT scan in the radiotherapy department.

The scan shows the cancer and the area around it. You might have other types of scans or x-rays to help your treatment team plan your radiotherapy. The plan they create is just for you.

Photo of a CT scanner

Your radiographers tell you what is going to happen. They help you into position on the scan couch. You might have a type of firm cushion called a vacbag to help you keep still.

The CT scanner couch is the same type of bed that you lie on for your treatment sessions. You need to lie very still. Tell your radiographers if you aren't comfortable.

Injection of dye

You might need an injection of contrast into a vein in your hand. This is a dye that helps body tissues show up more clearly on the scan.

Before you have the contrast, your radiographer asks you about any medical conditions or allergies. Some people are allergic to the contrast.

Having the scan

Once you are in position your radiographers put some markers on your skin. They move the couch up and through the scanner. They then leave the room and the scan starts.

The scan takes about 5 minutes. You won't feel anything. Your radiographers can see and hear you from the CT control area where they operate the scanner. 

Radiotherapy mould (shell)

Your treatment team might make a mould (shell) for you.

You wear it during the treatment sessions to keep you very still. The radiographers may also make marks on it. They use the marks to line up the radiotherapy machine for each treatment.

The process of making the shell can vary slightly between hospitals. It usually takes around 30 minutes.

Before making the shell

You need to wear clothes that you can easily take off from your neck and chest. You also need to take off any jewellery from that area.

Facial hair, long hair or dreadlocks can make it difficult to mould the shell. The radiotherapy staff will tell you if you need to shave or to tie your hair back.

Making the shell

A technician uses a special kind of plastic that they heat in warm water. This makes it soft and pliable. They put the plastic on to your face, neck and chest so that it moulds exactly. 

After a few minutes the plastic gets hard. The technician takes the shell off and it is ready to use.

Photograph of a mesh plastic mask used for radiotherapy for cancer of the head and neck and brain
You usually don't need a mould if you are only going to have radiotherapy to help control symptoms caused by the cancer. Ask your doctor if you need to have a mould before the start of treatment.

After your planning session

You might have to wait a few days or up to 3 weeks before you start treatment.

During this time the physicists and your radiographer doctor (clinical oncologist) decide the final details of your radiotherapy plan. They make sure that the area of the cancer will receive a high dose and nearby areas receive a low dose. This reduces the side effects you might get during and after treatment. 

The radiotherapy room

Radiotherapy machines are very big and could make you feel nervous when you see them for the first time. The machine might be fixed in one position or able to rotate around your body to give treatment from different directions. The machine doesn't touch you at any point.

Before your first treatment, your therapy radiographers Open a glossary item will explain what you will see and hear. In some departments the treatment rooms have docks for you to plug in music players. So you can listen to your own music while you have treatment.

Photo of a linear accelerator

Before your treatment

Your radiographers help you get into position on the treatment couch. They line up the radiotherapy machine, using the marks on your skin.

Then they leave you alone in the room for a few minutes for the treatment. This is so they aren't exposed to radiation. 

During the treatment

You need to lie very still. Your radiographers might take images (x-rays or scans) before your treatment to make sure that you're in the right position. The machine makes whirring and beeping sounds. You won’t feel anything when you have the treatment.

Your radiographers can see and hear you on a CCTV screen in the next room. They can talk to you over an intercom and might ask you to hold your breath or take shallow breaths at times. You can also talk to them through the intercom or raise your hand if you need to stop or if you're uncomfortable.

You won't be radioactive

This type of radiotherapy won't make you radioactive. It's safe to be around other people, including pregnant women and children.

Travelling to radiotherapy appointments

You might have to travel a long way each day for your radiotherapy. This depends on where your nearest cancer centre is. This can make you very tired, especially if you have side effects from the treatment.

You can ask the therapy radiographers Open a glossary item for an appointment time to suit you. They will do their best, but some departments might be very busy. Some radiotherapy departments are open from 7am till 9pm.

Car parking can be difficult at hospitals. Ask the radiotherapy staff if you are able to get free parking or discounted parking. They may be able to give you tips on free places to park nearby.

The radiotherapy staff may be able to arrange transport if you have no other way to get to the hospital. Your radiotherapy doctor would have to agree. This is because it is only for people that would struggle using public transport and have no access to a car. 

Some people are able to claim back a refund for healthcare travel costs. This is based on the type of appointment and whether you claim certain benefits. Ask the radiotherapy staff for more information about this.

Some hospitals have their own drivers and local charities might offer hospital transport. So do ask if any help is available in your area.

Side effects

The side effects of radiotherapy depend on which part of your body is treated. For example, radiotherapy to the neck can cause a sore throat and difficulty swallowing. Whereas radiotherapy to the tummy (abdomen) or pelvis, can make you feel sick or have loose poo (diarrhoea). 

You might feel tired while having radiotherapy. This is more likely if you are having treatment over a number of weeks.

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 might have very few side effects. The side effects gradually disappear in the days after your treatment has finished.

Last reviewed: 
26 May 2021
Next review due: 
26 May 2024
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