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Breast cancer radiotherapy side effects

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This page tells you about the possible side effects of radiotherapy for breast cancer. You can find information about

 

A quick guide to what's on this page

Side effects during breast radiotherapy treatment

Radiotherapy may cause side effects during the treatment. You may have reddening and soreness of the skin, discomfort and swelling of your breast, or tiredness. These effects start to get better when your treatment ends. But you may feel tired for some months afterwards.

Effect on other treatments

Radiotherapy may mean that you can't have some types of breast reconstruction surgery because radiotherapy can reduce the blood flow to the breast tissue. Some reconstruction techniques need a very good blood flow.

After your treatment

The radiotherapy may have some lasting effects on your skin and any breast tissue left behind after surgery. The remaining breast tissue may feel firmer and may gradually shrink. In some women it becomes tender. You may get small red marks on your skin caused by tiny broken blood vessels. This is not harmful. The skin may be darker and more sensitive and it is important to cover up in the sun.

If your breast becomes swollen, see your doctor or breast care nurse. The radiotherapy may have caused problems with the natural drainage of the tissues. The swelling is called lymphoedema.

Long term side effects

By far the most common long term side effects are the changes in appearance described above. Improved radiotherapy techniques mean more serious side effects are very rare. If you are worried about side effects, talk to your radiotherapy specialist and breast care nurse or look in the radiotherapy section.

 

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Side effects during treatment

Radiotherapy sometimes causes side effects during the treatment. You may not notice these effects until you have had a couple of weeks of treatment. They start to get better when your treatment ends. You may have

Reddening and soreness of the skin

Radiotherapy can make the skin go red or darker in the treatment area. Some people have no skin problems at all but others can have very sore skin. Whether or not you have a skin reaction depends on your own type of skin and the area being treated.

If you get a skin reaction it will be red (or darker in dark skinned people). It can also be sore, like a sunburn. It won't happen straight away but develops gradually after several sessions. Your radiographer looks out for these reactions. But let them know if you feel any soreness. If the skin gets very sore it may peel. But it should heal quickly. Skin reactions usually settle down two to four weeks after your treatment finishes.

You may also get redness or darkening on the other side of your body to the treatment area – for example, on your back if the front of the chest is being treated. This area where the radiotherapy beams leave the body is called the radiotherapy exit site. If the exit site skin becomes red or sore tell the radiotherapy unit staff.

There is information about caring for your skin during radiotherapy in the cancer treatment section.

Discomfort and swelling of your breast or chest area

The treatment can cause some swelling of the breast or chest area. The swelling usually goes down over a few weeks once the treatment ends. But let your doctor, nurse or radiographer know if the swelling continues. 

Tiredness

Tiredness tends to come on slowly as you go through your treatment. So you may not feel tired at the beginning of your course, but you are very likely to by the end. You may feel like having a sleep 1 to 2 hours after each radiotherapy treatment. This tiredness is called fatigue and you may also feel weak and as though you have no energy.

Tiredness can carry on for some months after your treatment has finished. Our tiredness and cancer section has tips on dealing with it. Some research into treating fatigue shows that exercise may be more helpful than rest. Try to schedule in a short walk each day. You may find that you can gradually increase the distance. Pick the time of day when you are feeling least tired.

 

Effect on other treatments

Radiotherapy may affect your chance of having some types of breast reconstruction, even if otherwise they may be suitable for you. Tissue expansion reconstruction is not usually possible after radiotherapy to the chest, because the skin is less stretchy afterwards. 

Some types of breast reconstruction using body tissue may not be possible. This is because the breast area needs a good blood supply for this type of reconstruction surgery. Radiotherapy lowers the blood flow to the area.

 

Side effects after treatment

The radiotherapy may have some lasting effects on your skin and any breast tissue left behind after breast conserving surgery. You may find that you have

For most women the appearance of the breast is very good after radiotherapy. But if you are worried about the possible side effects, you can speak to your radiotherapy doctor (clinical oncologist) or breast care nurse. You may also find it helpful to look at the main section about radiotherapy side effects.

Firmer breast tissue

The breast may feel hard due to a side effect called radiation fibrosis. The breast tissue becomes more fibrous and less stretchy. For many women, this is quite mild. But for some women the breast can become tender.

Shrinking of breast tissue

The breast tissue may also shrink over many years. The radiotherapy may make the breast tissue contract and this may make the breast gradually get smaller.

Swelling of the breast area

If your breast becomes swollen, see your doctor or breast care nurse. The radiotherapy may have caused problems with the natural drainage of fluid from the tissues. This is called lymphoedema (pronounced lim-fo-dee-ma) and is rare in the breast. Your doctor or nurse can refer you to a lymphoedema specialist, who can arrange for a type of massage called manual lymphatic drainage.

Small red marks on your skin

You may get small, red lines on the skin of the treated area due to tiny broken blood vessels. This is called telangiectasia (pronounced teel-an-gee-ek-tay-zee-a). This is quite a common side effect after radiotherapy. The broken blood vessels affect the look of the breast, but they don't cause any harm.

Darker skin

The skin in the treated area may gradually darken in the years after your radiotherapy. It can look like a deep tan. The skin in this area may be more sensitive and it is important to cover up with clothes or wear sunscreen if you are out in the sun.

 

Long term side effects

By far the most common long term side effects of radiotherapy are the change in appearance described above.

Some women get a swelling in the arm called lymphoedema after radiotherapy to the armpit, particularly if they have had surgery there too. These days, specialists do not recommend having both surgery and radiotherapy to the armpit due to the increased risk of lymphoedema. But surgery and radiotherapy to the armpit may both be needed if the lymph nodes there contain cancer cells.

Other more severe, but much rarer, long term side effects may occur. They are not common though, because treatment planning is very exact these days.

Rarely, you can get a continuing cough or breathlessness some years after radiotherapy to the chest. This is due to the radiotherapy causing changes in the lung tissue called radiation fibrosis. Doctors cannot predict who will get this rare side effect. 

Some people who have radiotherapy to the left side of their chest may have changes in their heart many years later. But this is very rare.

Women having radiotherapy for breast cancer often have treatment from more than one angle. In the past, sometimes part of the shoulder was treated twice – once from each angle. Doctors call that overlapping treatment fields. Nerves in the shoulder were sometimes badly damaged by having a high radiotherapy dose. That caused severe pain and difficulty in using the arm. These days, modern radiotherapy planning includes checks for overlapping radiation fields and so this should not happen.

 

Where to find more information

There is detailed information about radiotherapy side effects in the main radiotherapy section. 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.

There are also books and booklets about radiotherapy, some of which are free. Look on our breast cancer reading list. Or you can get in touch with one of the organisations listed on our breast cancer organisations page. Many offer counselling. To find out more about counselling look in our counselling section.

Radiotherapy may affect the type of reconstruction you can have. You may want to look at our information about types of breast reconstruction

If you are worried about side effects, particularly long term side effects, it is best to talk to your radiotherapy specialist and breast care nurse. They may be able to relieve your concerns. If you think you are developing any long term side effects, you need to see your own specialist.

There are a few questions for your doctor about breast radiotherapy at the end of this section.

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Updated: 1 August 2014