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About breast cancer radiotherapy

Radiotherapy is cancer treatment using radiation. It is a common treatment for breast cancer. After breast surgery, radiotherapy can lower the risk of the cancer coming back in the breast.

How and where you have radiotherapy

You have your treatment in the hospital radiotherapy department. You may have treatment once a day, from Monday to Friday, for 3 to 5 weeks. You usually have a break from treatment at the weekend. You travel to the hospital each time you have treatment.

At your first visit you lie under a specialised CT scanning machine. The doctors use the machine to plan your treatment. The radiographers will make one or more small tattoo marks on your skin. They use these to line up the radiotherapy machine accurately each time. They may also draw marks on your body with a felt tip pen.

Each treatment only takes a few minutes. The treatment doesn't hurt, and it does not make you radioactive.

More rarely a single treatment of radiotherapy is given into the breast tissue during surgery. But it is not clear whether this works as well long term as external radiotherapy. Another less commonly used treatment is radioactive tubes put into the area of the breast where the cancer was removed. Doctors call this internal radiotherapy or brachytherapy.


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What radiotherapy is

Radiotherapy is cancer treatment using radiation to destroy cancer cells. It is a common treatment for breast cancer after surgery. Studies have shown that for women with early breast cancer the cure rate is the same whether they have only the cancer removed (breast conserving surgery) followed by radiotherapy or have the whole breast removed (a mastectomy). 

Radiotherapy after breast conserving surgery

A review in 2011 looked at research trials into radiotherapy after breast conserving surgery. It showed that radiotherapy treatment lowers the risk of the cancer coming back either in the remaining breast tissue or in the nearby lymph nodes. It also helps some women live longer. You can read a brief summary of the review. It is written for researchers and specialists so is not in plain English.

Usually after breast conserving surgery (lumpectomy or wide local excision) women have radiotherapy to the whole of the remaining breast tissue. Doctors call this whole breast radiotherapy. But some trials are looking at giving radiotherapy just to the area where the breast cancer was removed using intensity modulated radiotherapy (IMRT). Other trials are looking at giving different doses of radiotherapy to particular areas of the breast. There is information about these trials on our breast cancer treatment research page.

Radiotherapy after mastectomy

Some women who have a mastectomy may need radiotherapy to the area of the chest where the breast was removed. The radiotherapy can reduce the chance of the cancer coming back in that area.

Breast radiotherapy impact statement


How and where you have radiotherapy

You have to travel to hospital for radiotherapy treatment. You have your treatment in the radiotherapy outpatient department. It is split into a course of small treatments. If you were to have the total dose in one go, it would harm normal body tissues too much. So radiotherapy doctors split the dose into smaller doses that you have each day (or on alternate days) over a number of weeks. They call each dose a fraction.

You may have treatment once a day for 3 to 5 weeks, from Monday to Friday, with a rest at the weekend. This means you will need to go to the hospital every weekday for that time. The length of your course of treatment will vary depending on your needs and the hospital where you are treated. The total dose of radiotherapy you get is usually about the same with each of these schedules.

Some trials are looking at giving radiotherapy in different doses. You can read about the trials on our page about research into breast cancer treatment.


Planning your 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 will 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. We have information about radiotherapy skin markings

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.


Having your radiotherapy

Radiotherapy machines are very big. The machine may be fixed in one position so that you move through it. Or it may be 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 while you have treatment.

You can't feel radiotherapy when you actually have the treatment. It is important to lie very still 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 radiographers leave you alone in the room for a few minutes. They watch you carefully through a window or on a closed circuit television screen. They may ask you to hold your breath or take shallow breaths during the treatment.

Having external radiotherapy does not make you radioactive. It is perfectly safe to be with other people, including children, throughout your treatment course.

Below is a short video showing what to expect when you have radiotherapy for breast cancer.

View a transcript of the video about breast cancer radiotherapy (opens in a new window).


Radiotherapy during surgery

The National Institute for Health and Care excellence (NICE) has issued draft guidance about a new type of radiotherapy for people with early stage breast cancer. The treatment is a single dose of radiotherapy given during surgery instead of a course of treatments after the surgery. A clinical trial in 2013 suggested that this new treatment, known as Intrabeam Radiotherapy, is likely to work as well as standard radiotherapy. The treatment is also called Targit (TARGeted Intraoperative radioTherapy).

Doctors put an applicator inside the breast after the surgeon has removed the breast cancer. Once the applicator is in exactly the right place, the doctors put a radioactive source inside it for 10 to 30 minutes. This gives radiotherapy directly to the tissue around the cancer. The rest of the operation then goes ahead as normal. So far, women don't seem to have had any serious side effects. The wound may take a little longer to heal after surgery with this type of treatment.

As the treatment is new and it is not completely clear that it will work as well as standard radiotherapy, doctors need to collect information about it and the side effects. It is currently only available in 6 hospitals in the UK as part of research. But NICE will make a decision later this year about whether it will be available on the NHS.


Internal radiotherapy

The National Institute for Health and Care Excellence (NICE) has also issued guidance about internal radiotherapy (brachytherapy) for breast cancer. Internal radiotherapy to the breast is also called a radiotherapy implant or breast brachytherapy. NICE says  that doctors can use internal radiotherapy to give radiation treatment after surgery if they use it as part of a clinical trial. 

Brachytherapy is a way of giving radiation directly to the area where the cancer was removed. You have a general or a local anaesthetic. Thin hollow tubes or an inflatable balloon are put into your breast. Later, radioactive wires are passed through the middle of the tubes or a small radioactive metal source is put into the balloon.

Diagram showing how you have internal radiotherapy for breast cancer

The radioactive wires may be left in place for a few days, or just inserted for a few minutes. If you are having high dose treatment, you have the treatment for a few minutes over several days. Balloon brachytherapy is always given in short daily sessions. If the wires are left in place for a few days, then you stay in hospital, in a single room. 

Your friends and family will only be allowed to visit for a short time each day. This is so they won't be exposed to radiation. Children and pregnant women will not be allowed to visit you at all.

The radioactivity is in the wires. So the radioactivity goes away when the doctor takes the wires out. Then it is completely safe for you to be with other people including children.

There is information about treatment with radioactive wires in the main radiotherapy section and in our breast cancer research section.


More information about radiotherapy

There is detailed information about radiotherapy in our main radiotherapy section. You can find information about

We also have information about the possible side effects of breast radiotherapy.

If you have questions you can phone the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday. They will be happy to answer any questions that you have.

If you want to find people to share experiences with online, you could use Cancer Chat, our online forum.

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Updated: 31 July 2014