Side effects

Common

Pink, red, dry and itchy skin
This ranges from the slight pinkness of mild sunburn, through to redness and blistering. The skin will remain dryer and firmer. Your skin may be sensitive for several months after treatment.
Tiredness
This usually starts about 2 weeks after commencing treatment and gets worse until about 2-3 weeks after treatment. Some women are tired for several months after treatment.
Muscle inflammation
The muscle above and behind your breast may get sore and stiff after treatment is finished.

Lung scarring
This is permanent when it occurs and may show up later on a chest x-ray. You may get a cough or shortness of breath after treatment is finished.
Feeling sick
This mainly occurs in the first week or two after starting treatment. It is not usually bad enough to cause vomiting.
Lymphoedema
Radiation therapy can destroy lymph nodes and lympheodema can occur at any time later.
Heart damage
Older techniques may have increased the risk of heart problems. While modern therapy generally avoids the heart there is a slightly increased risk of heart attack after treatment to the left breast.
Sarcoma (another cancer)
May occur more than 5 years after treatment. It is very rare.