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 treatment 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.

Skin reaction

During treatment your skin may become red, itchy or irritated. The skin in your armpit, under your breast or around your nipple may be most affected due to friction. Your treatment team will apply a dressing called Mepitel Film at the beginning of your treatment. This reduces the friction between your skin and clothing and has been shown to reduce the severity of skin reactions experienced during radiation therapy. For areas where the film is not applied, your treatment team will provide you with a moisturising cream to use. Towards the end of treatment, the skin reaction can become more intense however usually returns to normal four to six weeks after treatment finishes. Tell your treatment team if you’re worried about a skin reaction or if you experience any skin changes.


You may feel tired or lack energy for daily activities during your treatment. This is a common reaction to radiation therapy and each person can be affected differently. 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 nodes are in the treatment field. Tell your treatment team 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.

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 treatment 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 treatment team if you notice any swelling in your arm or hand during treatment.

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

How can I manage my skin during treatment?

Moisturise twice a day

Your treatment team will provide a cream to help manage any skin changes. At the start of your treatment, apply cream to the area being treated twice a day where there is no film applied. As treatment progresses, you may need to apply the cream three to four times per day. Let your treatment 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 temperatures, such as direct sunlight, heat packs, ice packs, electric blankets, saunas, hot spas or swimming in chlorinated pools.

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 being removed, and/or radiation therapy. There are effective treatment programs that can reduce the swelling and risk of complications.

The earlier lymphoedema is recognised, the better we are able to help you manage it. Please report any symptoms or concerns to your treatment team and we may refer you to a lymphoedema specialist if required.

Common 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 treatment 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 eight weeks of finishing your treatment.

Will radiation make me radioactive?

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.

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  • 04 896 0200
  • Level B3, Bowen Specialist Medical Centre 98 Churchill Drive Crofton Downs Wellington 6035