Radiation therapy for breast cancer

Also known as radiotherapy, radiation therapy uses a controlled dose of radiation to kill cancer cells or damage them so they cannot grow, multiply or spread. The radiation is usually in the form of x-ray beams.

Learn more about:

• When is radiation therapy recommended?
• Planning radiation therapy
• Having radiation therapy
• Side effects of radiation therapy
• Video: What is radiation therapy?

When is radiation therapy recommended?

Radiation therapy is recommended:

• after breast-conserving surgery
• after a mastectomy – if pathology results suggest the risk of recurrence is high or if the cancer has spread to the lymph nodes you may have radiation to the chest wall and lymph nodes above the collarbone
• if the sentinel node is affected – you may have radiation to the armpit instead of axillary dissection.

You will usually start radiation therapy within eight weeks of surgery. If you’re having chemotherapy after surgery, radiation therapy will begin about three to four weeks after chemotherapy has finished. In some circumstances, radiotherapy may be offered after neoadjuvant chemotherapy and before surgery.

Planning radiation therapy

Treatment is carefully planned to have the greatest effect on the cancer cells and to limit damage to the surrounding healthy tissues. Planning involves several steps, which may occur over a few visits.

You will have a planning session at the radiation therapy centre. During this appointment, you will have a CT scan to pinpoint the area to be treated, and marks will be put on your skin so the radiation therapists treat the same area each time. These marks are small dots (tattoos), and they may be temporary or permanent. Talk to your radiation therapists if you are worried about these tattoos.

Having radiation therapy

You will probably have radiation therapy daily from Monday to Friday for 3–6 weeks. Usually you can have radiation therapy as an outpatient and go to the treatment centre each day.

Each radiation therapy session will be in a treatment room. Although you will get radiation for only 1–5 minutes, setting up the machine can take 10–30 minutes. You will lie on a table under the machine.

The radiation therapist will leave the room and then switch on the machine, but you can talk to them through an intercom.

Radiation therapy is not painful, but you will need to lie still while it is given. If the cancer is located on the left side, the radiation therapist may ask you to take a deep breath for 20–30 seconds during the treatment. This helps to inflate the lungs and rib cage, to move them away from the radiation field and minimise damage to the heart. This technique is known as deep inspiration breath hold.

Side effects of radiation therapy

Radiation therapy may cause the following side effects:

Tiredness

You may start to feel tired or lack energy for day-to-day activities 1–2 weeks after radiation therapy begins. Fatigue usually eases a few weeks after treatment finishes.

Red and dry skin  

The skin at the treatment area may become dry and itchy. Your skin may look red or sunburnt after a few weeks of treatment. It usually returns to normal 4–6 weeks after treatment ends. The nurses will show you how to care for your skin. Sorbolene cream applied twice a day can be helpful.

Skin problems

Less commonly, your skin may peel or become very irritated. The treatment team will closely monitor your skin, and you may need dressings or creams to help the area heal.

Aches

You may feel minor aches or shooting pains that last for a few moments during treatment.

Swelling

Some people develop fluid in the breast (oedema) that can last for up to 12 months or, in some cases, longer. Radiation therapy to the armpit may increase the chance of developing lymphoedema in the arm. Talk to your radiation oncologist or radiation oncology nurse about any changes you experience.

Hair loss

Radiation therapy to the breast may cause you to lose hair from the treated armpit but doesn’t cause you to lose head hair.

Other side effects

Other side effects can develop months or years after radiation therapy. These are called late effects.

Part of the lung behind the treatment area may become inflamed, causing a dry cough or shortness of breath.

There is a slight risk of radiation therapy causing heart problems, but this usually happens only if you have treatment to your left breast or you smoke. In rare cases, radiation therapy may cause a second cancer.

For more on this, see our general section on Radiation therapy.

Video: What is radiation therapy?

Watch this short video to learn more about radiation therapy.