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 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.

Radiation therapy does not make you radioactive and it is safe to be around others, including children and pregnant women during and after your treatment. There is no restriction on physical contact with others.

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.

Short-term side effects may include:

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 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 subside when treatment finishes. Please talk to your nurse if the swelling gets worse or is uncomfortable. It is not uncommon to feel minor twinges or pain the breast area. This will also subside once treatment is completed.


You may feel tired or lack energy for daily activities during your treatment. This is a common reaction to radiation therapy and each person is usually affected to varying degrees. Finding a balance between rest and activity with help you manage daily life.

Sore throat

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

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 whilst on 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 any creams without one hour of treatment. 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 and lace bras. Your nurses can advise ways to keep high risk areas dry and reduce friction or rubbing.

Avoid excessive temperatures

Avoid exposure of the treatment areas to excessive temperatures, such as direct sunlight, heat packs, ice packs, electric blankets, saunas or hot spas.

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 the skin dry – do not rub/

Do not shave or use deodorants or talcum powder under the arm on the side being treated. 


Prescriptions and vitamins

You should continue to take any prescribed medications as normal. Please inform your nurse if you are taking vitamins, antioxidants or herbal supplements, or if you start on 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 bring removed, and/or radiation therapy. There are effective treatment programs that can reduce the swelling and risk of complications. Your nurses can assist with the 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?

We ask that you don’t deliberately wash them off as this may further irritate your skin. Your radiation therapists will re-apply them each day 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 four to six weeks of finishing your treatment.

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.

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