Possible side effects of radiotherapy for DCIS

You may develop side effects over the course of your treatment. These usually disappear gradually over a few weeks or months after treatment finishes. Your doctor, nurse or radiographer will discuss this with you so you know what to expect. Let them know about any side effects you have during or after treatment, as there are often things that can be done to help.

Skin changes

Your skin in the treated area may get red, dry and itchy. Dark skin may get darker or have a blue or black tinge. Your nurse or radiographer will give you advice on looking after your skin. If it becomes sore and flaky, your doctor can prescribe creams or dressings to help. Skin reactions settle down 2–4 weeks after radiotherapy.

Here are some tips to help with skin irritation:

  • Don’t put anything on your skin in the treated area without checking with your nurse or radiographer first.
  • Have a tepid or warm shower rather than a bath if you can. Turn away from the spray to protect your breast.
  • Pat the area dry gently with a soft towel. Don’t rub the skin.
  • Wear loose clothing or crop tops, as they are less likely to irritate your skin.

You need to avoid exposing the treated area to sunshine for at least a year after treatment finishes. Use suncream with a high sun protection factor (SPF) of at least 30 to protect your skin.

Tiredness (fatigue)

You’re likely to become tired and have to take things slowly. Try to pace yourself and save your energy for things that you want to do or that need doing. Balance rest with some physical activity – even going for short walks will help increase your energy levels.

Aches and swelling

You may have a dull ache or shooting pains in the breast that last for a few seconds or minutes. You may find that your breast becomes swollen during treatment. These effects usually improve quickly after treatment. Some women still have occasional aches and pains in the breast area after radiotherapy.

Long-term side effects

Radiotherapy to the breast can sometimes lead to long-term side effects, but most of these are rare.

If you continue to have pain or discomfort after treatment, talk to your doctor or breast care nurse.

The most common effect is a change in how the breast looks and feels. Small blood vessels in the skin can be damaged, which can cause red ‘spidery’ marks on the skin (telangiectasia). Your breast may feel firmer and shrink slightly in size. Some women choose to have surgery to improve the appearance of their breasts. You may be offered surgery to reduce the size of the untreated breast or to make the treated breast larger.

It’s rare for radiotherapy to the left breast to cause any heart problems. Lung or rib problems because of radiotherapy are also rare.

Back to Radiotherapy explained

Radiotherapy for DCIS

Radiotherapy after surgery reduces the risk of DCIS coming back and of an invasive cancer developing.