Radiotherapy for breast cancer

Radiotherapy uses high-energy rays called radiation to treat cancer. It destroys cancer cells in the area where the radiotherapy is given, while doing as little harm as possible to normal cells.

Some normal cells in the area being treated can also be damaged by radiotherapy. This can cause side effects. As the normal cells recover, the side effects usually get better.

Radiotherapy is always carefully planned by a team of experts. They will plan your treatment so it does as little harm as possible to normal cells.

Radiotherapy reduces the risk of breast cancer coming back in the area it is given to. You usually start radiotherapy 4 to 6 weeks after surgery. Sometimes it may start later.

For example, you may start radiotherapy later if your wound needs more time to heal properly. If you are also having chemotherapy, you have radiotherapy after chemotherapy.

Radiotherapy is a standard treatment for breast cancer. But it may be offered as part of a clinical trial.

You may still need radiotherapy to the chest after a mastectomy. This will depend on the risk of the cancer coming back in that area. You are more likely to have radiotherapy if:

• the cancer was large
• the cancer had spread to the lymph nodes in the armpit
• there were cancer cells close to the edge of the removed breast tissue.

You have radiotherapy as an outpatient. It is usually given using equipment that looks like a large x-ray machine. This is called external beam radiotherapy (EBRT) or external radiotherapy. The person who operates the machine is called a therapy radiographer. They will give you information and support during your treatment.

You usually have radiotherapy as a series of short daily treatments. Each treatment is called a fraction or a session. You usually have 5 sessions over 1 week. Sometimes you have 15 sessions over 3 weeks. Your cancer doctor will tell you how many sessions you will need.

If you had breast-conserving surgery, you may have extra radiotherapy to the area where the cancer was. This is called a radiotherapy boost.

Sometimes the boost is given at the same time as radiotherapy to the rest of the breast. Or it may be given at the end of the treatments. This means you may need a few more treatments after finishing your main course of radiotherapy.

If you have radiotherapy to your left side, you will usually be asked to take a deep breath and hold it briefly. This is called deep inspiration breath hold (DIBH). You do this at each of your planning and treatment sessions. DIBH helps protect your heart during radiotherapy treatment to your left side.

Your heart is on the left side of your chest. DIBH moves the heart away from the area being treated. It also keeps you still and reduces the risk of late effects. The website respire.org.uk explains more about DIBH. You may have intensity-modulated radiotherapy (IMRT). This is another type of external radiotherapy. It shapes the radiotherapy beams and allows the radiographer to give different doses of radiotherapy to different areas. This means you have lower doses of radiotherapy to healthy tissue surrounding the tumour.

External radiotherapy does not make you radioactive. After treatment, it is safe for you to be with other people, including children.

Less commonly, you may be offered radiotherapy to part of the breast instead of the whole breast. This way of giving radiotherapy is usually only given to people having breast conserving surgery.

Men only have a small amount of breast tissue and usually have a mastectomy.

Your cancer doctor or nurse will explain if this is an option for you. They will tell you what the possible side effects are, and any risks involved. They can explain how these treatments compare with external radiotherapy. It is important to have information about all your treatment options.

Radiotherapy to part of the breast can be given in different ways:

Radiotherapy to the breast may cause side effects that happen months or years after radiotherapy. These are called late effects. Newer ways of having radiotherapy are helping reduce the risk of late effects. If you are worried about late effects, talk to your cancer doctor, breast care nurse or radiographer.

The most common late effect is a change in how the breast or chest area looks and feels.

Radiotherapy can damage small blood vessels in the skin. This can cause red, spidery marks to show. These are called telangiectasia. They may be more common if you had boost doses of radiotherapy.

After radiotherapy, your breast may feel firmer and shrink slightly in size. If your breast is noticeably smaller, you can have surgery to reduce the size of your other breast. If you had breast reconstruction using an implant before radiotherapy, you may need to have the implant replaced.

You may find the treated area sore or uncomfortable for some time. This usually improves over years. It is not uncommon to get pain in the muscle or ribs at the edge of the breast if you overdo things. Very rarely, radiotherapy may cause lung problems or problems with the ribs.

If you have radiotherapy to the left breast, very rarely it can cause heart problems. Tell your cancer doctor, nurse or radiographer if you notice any problems with your breathing, or have any pain in the chest area. We have more information about the late effects of breast cancer treatment.