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Radiotherapy reduces the risk of DCIS coming back and of developing an invasive cancer in that breast.
Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells while doing as little harm as possible to normal cells.
It’s given after surgery| for DCIS, and if you’ve been advised to have it, your cancer specialist will explain why it’s recommended in your situation. It’s important to talk about any concerns you may have with your specialist and your breast care nurse.
You are more likely to need radiotherapy if:
The treatment is normally given in the hospital radiotherapy department as a series of short daily sessions. The treatments are usually given from Monday–Friday, with a rest at the weekend. Each treatment takes 10–15 minutes. Your doctor will discuss the treatment and possible side effects with you.
A course of radiotherapy for DCIS usually lasts three weeks but may be up to five weeks in some centres. It’s given to you as an outpatient.
External radiotherapy does not make you radioactive, and it’s perfectly safe for you to be with other people, including children, after your treatment.
To ensure that you receive maximum benefit from your radiotherapy, it has to be carefully planned. This is usually done using a CT scanner, which takes x-rays of the area to be treated. Treatment planning is a very important part of radiotherapy, and it may take a few visits before the clinical oncologist (the doctor who plans and supervises your treatment) is satisfied with the result.
Marks will usually be drawn 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 throughout your treatment, and permanent marks (like tattoos) may be used. These are tiny, and will only be done with your permission. You may feel a little discomfort while it’s being done.
The radiotherapy is normally given to the whole breast. You may also be given an extra dose to the exact area where the DCIS was. This is known as a booster dose.
Before each session of radiotherapy, the radiographer will position you carefully on the couch and make sure you are comfortable. During your treatment you will be left alone in the room, but you will be able to talk to the radiographer, who will be watching you from the next room. Radiotherapy is painless, but you have to be still for a few minutes while the treatment is being given.
You’ll need to be able to position your arm so that the radiotherapy machine can give the treatment effectively. Sometimes your muscles and shoulder joint may feel stiff.
If you can’t move your shoulder normally, it may be painful or difficult to give the treatment. A physiotherapist may teach you some exercises to make the position for treatment feel easier.
Radiotherapy to the breast sometimes causes side effects such as skin irritation, tiredness, and aches and swelling.
These side effects will usually gradually disappear over a few weeks or months after treatment is finished. Your doctor, nurse or radiographer will discuss this with you so that you know what to expect. Let them know about any side effects that you have during or after treatment. There are often things that can be done to help.
You may develop redness, dryness and itching of the skin in the treatment area. If you are dark skinned, your skin may get darker or have a blue or black tinge. Your doctor can prescribe creams to soothe your skin if it becomes sore and flaky.
Usually any skin reaction settles down 2–4 weeks after radiotherapy. You’ll be given advice on looking after your skin in the area being treated.
Here are some tips:
You’ll need to avoid exposing the treated area to sunshine for at least a year after treatment. If skin is exposed, use high sun protection factor (SPF) suncream to protect it.
You’re likely to feel tired during treatment, and this may continue for a month or two after it finishes. Pace yourself and save energy for the things you enjoy and things you have to do. Get plenty of rest but balance this with gentle, regular exercise such as short walks, which will give you more energy.
We have information on coping with tiredness| (fatigue).
You may notice a dull ache or shooting pains in the breast that lasts for a few seconds or minutes. Sometimes your breast might become swollen during treatment but this usually improves quickly after treatment is finished. Some women continue to have occasional aches and pains in the breast area after radiotherapy.
Radiotherapy to the breast can sometimes lead to long-term side effects, but most of these are rare.
After radiotherapy some women develop red ‘spidery’ marks (telangiectasia) on the skin because small blood vessels are damaged. These affect how the breast looks but are harmless. Your skin may also have a slightly darker tone. It’s not unusual for the breast to feel firmer, and over months or years, it may shrink slightly in size.
Let your surgeon or breast care nurse know if you’re unhappy with the shape of the treated breast or if it isn’t the same size as your other breast. There are often reconstructive techniques that can be done to improve this.
Rarely a few months after radiotherapy some women develop breathlessness due to the effect of radiotherapy on the lung. It usually gets better within 2–4 weeks without any treatment or with a short course of steroid medicines. Radiotherapy rarely causes any long-term damage to the lungs.
Although some women may worry about the effects of radiotherapy on the heart, it is now very carefully planned to avoid including the heart in the treatment area. It very rarely causes heart problems, and only women who had DCIS in their left breast are at risk. You can read how lifestyle changes| can help you look after your heart.
Rarely, radiotherapy weakens the ribs in the treated area, making them more likely to fracture than normal.
If you’re worried about the risk of developing particular side effects from radiotherapy, talk it over with your clinical oncologist (radiotherapist).
We have more information about radiotherapy| and the possible long-term side effects of radiotherapy| for breast cancer.
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.