Radiation therapy to the breast

Radiation therapy to the breast

Knowing what to expect during and after treatment can help you prepare and reduce any anxiety that you may be feeling. The following information has been put together to help you understand your radiation therapy treatment, and we hope to reduce any concerns you have. It does not replace discussion with your doctor, or the advice of your care team specific to your needs.

What is radiation therapy?

Radiation therapy is the use of radiation to safely treat and manage cancer.

Radiation oncologists use radiation to destroy cancer cells, reduce their growth or relieve symptoms of cancer. Radiation therapy works by damaging cancer cells while limiting the impact to healthy cells. It works because cancer cells are more sensitive to radiation than healthy, normal cells. When a small dose of radiation is given each day over several weeks, normal cells can recover from the radiation, but cancer cells cannot. It is typically a painless treatment, similar to having an x-ray, and only affects the part of the body
being treated.

What are the possible short-term side effects?

Radiation therapy may cause side effects. Everyone is different and you’re unlikely to experience all of the side effects listed below.

We encourage you to talk to us about any side effects that worry you. We are here to help you find ways to manage any side effects that you experience.

Skin reaction

Two to three weeks after treatment starts your skin may become red, itchy or irritated. This reaction can last the remainder of your treatment, and usually returns to normal four to six weeks after treatment finishes.

Towards the end of treatment, the skin reaction can become more intense and may continue to increase for up to two weeks after treatment finishes. You may experience some minor skin loss in the armpit, under the breast, in the nipple or neck area. This can be managed with a simple dressing until the area heals.

Your nurses will show you how to care for your skin during treatment and manage any skin reactions. Tell your nurse if you’re worried about a skin reaction or if you experience any skin changes.

Swelling, aches and pains in the breast area

You may notice mild swelling in the breast or under your arm. This is normal and will improve when treatment finishes. Please talk to your care team if the swelling gets worse or is uncomfortable. It’s not uncommon to feel minor twinges or pain in the breast area. This will also improve once treatment is completed.

Moderate swelling can persist six to eight weeks after treatment and can be uncomfortable. Mild swelling may persist for up to one year or more. Please advise your care team if you notice any swelling in your arm or hand during treatment.


You may feel tired or lack energy for daily activities during your treatment. You may feel increasingly tired as you reach the end of your treatment. This is a common reaction to radiation therapy and each person is usually affected to varying degrees. Fatigue usually eases a few weeks after treatment finishes. Finding a balance between rest and activity will help you manage daily life.

Sore throat

You may develop a mild sore throat if your neck is in the treatment field. Tell your nurse if you are experiencing a sore throat.

Increased firmness

Mild to moderate firmness can occur in the treated breast, and remain for up to eight weeks after treatment. This doesn’t usually require intervention.

Your radiation oncologist will talk to you about any long-term side effects that relate to your treatment.

How can I manage my hair and skin during treatment?

Moisturise twice a day

Your care team will recommend a cream to help manage any skin changes. At the start of your treatment, apply cream to the area being treated twice a day. As treatment progresses, you may need to apply the cream three to four times per day. Do not apply cream within the hour prior to your treatment, as cream needs to be well absorbed. Let your nursing team know if you continue to experience skin changes.

Wear loose fitting clothing

Avoid wearing tight fitting clothing that could potentially rub or irritate the skin. You may find singlets, cotton ‘crop-tops’ or loose fitting bras more comfortable. Avoid underwire or lace bras.

Avoid excessive temperatures

Avoid exposing the treatment area to excessive temperature including direct sunlight, heat packs, ice packs, saunas or hot spas during the course of your radiation therapy.

Wash with warm water and pat dry

You may wash the skin that is being treated with warm water and a mild non-perfumed soap. Pat dry the skin – do not rub.

Do not shave or use deodorants or talcum powder under the arm on the side being treated. Do not apply sunscreen to the treatment area.


Prescriptions and vitamins

Continue to take any prescribed medications. Please inform your nurse if you’re taking vitamins, antioxidants or herbal supplements and if you start any new medications during your treatment.

If you have any questions regarding medications please discuss this with your radiation oncologist or nurse.


Lymphoedema is swelling of the arm and/or other limb caused when the lymphatic system does not function properly. Over time this swelling increases and can lead to a feeling of heaviness and discomfort in the area. If left untreated, it can lead to reduced mobility and function.

Secondary lymphoedema can result from damage to the lymphatic vessels and/or lymph nodes. This may be from surgery, the lymph nodes being removed, and/or radiation therapy. There are effective treatment programs that can reduce the swelling and risk of complications. Your nurses can assist with management techniques and teach you how to self-manage your lymphoedema at home.

The earlier lymphoedema is recognised, the better we are able to help you manage it. We may also refer you to a lymphoedema specialist if required.

Frequently asked questions

How will radiation therapy affect my day-to-day life?

You may continue your usual work and daily activities, but you may need to rest more than usual due to tiredness or fatigue during treatment. Unless otherwise advised, you can eat and drink normally. Alcohol consumption in moderation is permitted, and you can continue to take any prescribed medications.

Can I wash the marks off my skin?

You may have a combination of permanent or temporary marks on your skin. We ask that you don’t deliberately wash temporary marks off as this may further irritate your skin. Your radiation therapists will re-apply them as required.

What happens after my treatment is finished?

Reviews and follow-up appointments will be discussed and organised by your care team prior to completing treatment.

When should side effects settle?

Radiation therapy treatment keeps working even after you have stopped coming in for regular treatment. This means symptoms may get a little worse before they get better. Generally, side effects will settle within two to four weeks of finishing your treatment.

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