Breast radiation side effects


Radiation therapy, also called radiotherapy, is a very effective treatment for lowering the risk of recurrence in early-stage breast cancer and for managing pain or complications of metastatic breast cancer. While radiation therapy itself isn’t painful, there are side effects that can feel uncomfortable. This is because while radiation destroys cancer cells, it also damages healthy cells near the area being treated.

It’s completely normal to be concerned about potential side effects of radiation therapy. Your healthcare team is there to support you and help you manage side effects. We’re here for you too, with information about what you might experience and things you can do to feel better.

As you prepare for radiation treatment, consider what you may want to ask your team, such as:

  • What kinds of side effects can I expect? When are they most likely to start?
  • Are there side effects I should let you know about immediately?
  • Can you recommend ways I can take care of my skin during treatment?

The type and intensity of radiation therapy side effects you may experience depend on a number of factors, such as:

  • Your skin type; different skin types and colors can be affected by radiation in different ways
  • The location and characteristics of the breast cancer
  • The kind of radiation your doctor has recommended, such as external beam radiation or brachytherapy (internal radiation)
  • The dose of radiation you’re receiving
  • Any other treatments you’ve received, such as surgery or chemotherapy
  • Your treatment schedule

You can learn more about the different types of radiation and why they are recommended on the Radiation therapy for breast cancer page.


Short-term side effects

Here are some of the most common side effects of radiation therapy to the breast that usually begin and end within a limited period of time.

Skin changes

About 2 or 3 weeks after your first treatment, you may begin to notice changes in the skin of the radiated treatment area. Skin changes that can happen with external beam radiation (and sometimes with internal radiation such as brachytherapy) can include:

  • Dryness
  • Irritation
  • Flakiness
  • Bruising (mainly with brachytherapy)
  • Sensitivity to sunlight
  • Skin color changes

Your doctor will recommend gels, lotions, or ointments that can help relieve these types of skin side effects. LBBC talked with breast surgical oncologist Monique Gary, DO, MSc, FACS about skin changes that can happen during radiation. She explained, “…cells begin to die, and melanocytes — the pigment cells — rise to the surface. That creates a darker skin tone for women of color. For Caucasian women, you see more pink and reddening of the skin.” Dr. Gary recommends sunscreen of 50 SPF or higher for everyone during and after radiation therapy, because the skin becomes very sensitive during and after radiation.


You can hear more of Dr. Gary’s recommendations for skin care during radiation therapy in our full video interview.

Radiation dermatitis, or radiodermatitis, is a very common skin rash that can happen during radiation therapy. Symptoms can include darkening of the skin (“hyperpigmentation”), burning, itching, swelling, skin thinning, and peeling. If you experience these symptoms, your doctor may recommend topical steroids or other treatments. Skin side effects can sometimes last 3-4 weeks after the final radiation treatment. If any skin side effects remain after that, they usually resolve in about 3 months.


Fatigue is an overall lack of energy. Fatigue isn’t just physical tiredness; it’s also mental and emotional tiredness that can leave you feeling wiped out.

Fatigue doesn’t happen for everyone undergoing radiation treatment. If it does happen, it usually starts a few weeks after beginning radiation therapy. As treatment continues, symptoms can increase, and resting doesn’t always bring relief.

If you’re feeling fatigue, it’s important to let your radiation treatment team know. Tell them if you’re having trouble focusing, doing daily activities, or getting out of bed. It’s especially important to let them know if fatigue is not improving, or if it’s getting worse. Your team can work with you on lifestyle strategies that may provide relief. These can include a physical exercise plan, nutrition adjustments, or relaxation techniques.

The good news is that like other short-term side effects, fatigue usually goes away after you finish radiation therapy.

Swelling & soreness

For some people, radiation therapy can cause fluid to temporarily build up in or around the breast. Radiation can also cause your breast, shoulder, or arm to feel sore or stiff and inflexible.

For stiff shoulders, talk to your radiation treatment team about exercises you can do to stay flexible. Symptoms of sore or swollen breasts usually go away several weeks after radiation therapy ends.

If you have radiation therapy to the lymph nodes, fluid can sometimes build up and cause swelling in the breast, chest, shoulder, or arm. This condition is called lymphedema, and there are ways to manage it — especially if it’s caught early. If it happens, lymphedema can develop shortly after radiation therapy is finished, or it can develop months or years later. Visit Lymphedema to learn more.


Nausea can also be a side effect of radiation therapy. Nowadays, nausea is very easy to manage with medicine. If you’re experiencing nausea, ask your radiation team for medication that can prevent or reduce nausea.


Long-term side effects

Some side effects of radiation therapy to the breast don’t show up until months or years later. These side effects don’t happen to everyone, and if they do happen, there are ways to manage them.

Scar tissue

Radiation fibrosis, or scar tissue, can sometimes develop years after radiation therapy. This can happen if radiation damages blood vessels in healthy tissue, cutting off blood supply to the tissue and causing it to harden. Symptoms can include tenderness and firmness. If radiation fibrosis is not treated, for some people, it can lead to muscle pain, tightness, or pain from nerve damage (neuropathy).

There are ways to reduce the effects of radiation fibrosis, including:

  • Physical therapy to improve range of motion
  • Massage to break down scar tissue
  • Pain-relieving medication

Spider veins

Telangiectasia or “spider veins” on the radiated skin may happen months or years after treatment. While this change can be permanent, it may fade with time. If you’re concerned about telangiectasia, talk with your radiation team. Your radiation oncologist can refer you to a dermatologist to talk about the possibility of laser treatment. Sometimes laser treatments can make telangiectasia less noticeable.

Lung inflammation

Lung inflammation (radiation pneumonitis) can sometimes happen with breast radiation, although it doesn’t happen often. Symptoms may not start until 3-6 months after radiation therapy is finished. Symptoms can include:

  • Shortness of breath
  • Cough
  • Chest pain that feels worse when taking a deep breath
  • Low-grade fever

Sometimes, there are no symptoms and lung inflammation is found on a chest x-ray. If you do have symptoms, they usually go away without any treatment. For people who need treatment, steroids are usually used. Lung inflammation after breast radiation is more likely if you have other lung conditions, such as emphysema. A technique called deep inspiration breath hold (DIBH) may help reduce the risk of lung inflammation after breast radiation.

Anyone, with or without cancer, should see a doctor if they feel shortness of breath, or have chest pain or excessive coughing, as these can be symptoms of many serious illnesses and may not be side effects of cancer treatment. Your doctor will be able to tell you if radiation therapy is causing these side effects.


Lymphedema - a condition that causes fluid buildup and swelling in the breast, chest, shoulder, or arm — can sometimes happen after radiation therapy to the lymph nodes. For some people, lymphedema can develop months or years after radiation therapy. There are ways to manage lymphedema if it’s caught early. Visit Lymphedema to learn more. If you notice new side effects months or years after you finish radiation therapy, let your healthcare team know.


Rare side effects

There are some long-term breast radiation side effects that are very rare, but can happen.

Heart damage can be a rare long-term side effect of radiation therapy. This is more of a risk if the left side (closer to the heart) is being treated. Deep inspiration breath hold (DIBH) has been shown to effectively reduce radiation exposure to the heart.

Other rare side effects include rib weakening that can lead to fractures, and nerve damage in the arm that can lead to arm tingling or weakness.

Also very rarely, radiation therapy can lead to another cancer, such as certain carcinomas and lung cancer. The risk is very small and doctors generally find the benefits of radiation are much greater than the risk of it causing another cancer.


Coping with physical side effects

There are many things you and your radiation team can do to relieve side effects.

Try these tips for managing skin side effects:

  • Wear loose clothing that’s soft and comfortable when it touches the treatment area.
  • Be gentle when you wash. Choose mild, fragrance-free soap and warm water. When drying, pat gently with a clean towel during the time you’re receiving radiation therapy treatments, and in the first few weeks after treatment ends.
  • Try to avoid rubbing or scratching the area.
  • Avoid using bandages or makeup on the area.
  • Your doctor will recommend or prescribe gels, ointments, or lotions to keep your skin moisturized and relieve irritation. Stick to the brands your doctor recommends to make sure you’re treating your skin safely.
  • Ask your radiation team for sunscreen recommendations to protect sun-sensitive treatment areas. It’s also a good idea to keep the area safe from direct sunlight with protective clothing. Clothes that help protect from sun damage usually have “UPF” (ultraviolet protection factor) on the label.

For help with fatigue, ask your healthcare team about these strategies:

  • Physical activity or exercise
  • Counseling to help shift your thoughts about fatigue and for help managing sleep issues
  • Complementary therapies such as relaxation techniques or music therapy
  • Nutrition adjustments
  • Medications

There’s also help for other, long-term radiation side effects:

  • For swelling, stiffness, or soreness, ask your treatment team about physical therapy or a referral to a lymphedema specialist for more serious swelling that isn’t going away.
  • For radiation fibrosis or scar tissue, physical therapy, massage, and pain relieving medication can be helpful. Your radiation oncologist should be able to refer you to a specialist who can help.
  • If you’re concerned about radiation-caused telangiectasia or spider veins, talk with your doctor about the option of laser therapy.
  • If you develop a cough, shortness of breath, or chest pain, tell your doctor right away. While these could be symptoms of temporary lung inflammation, they can also be symptoms of much more serious conditions that are not related to cancer.

Coping with emotional side effects

Daily radiation therapy treatments can trigger many different emotions. Fear, anger, or sadness can come up at any point in treatment. Coming to the treatment center every day can be a regular reminder of your diagnosis, fears about cancer coming back, and for many people, the entire cancer experience. In other words, it can feel overwhelming.

Fortunately, there are ways to get the treatment you need and still have some balance in your life. Katharine Winner, MSW, LSW, who works closely with radiation oncologists to provide emotional support to people receiving radiation therapy, says, “It’s important to find a balance between treatment and everyday life, when possible, to help maintain a sense of normalcy. We can help arrange your schedule to accommodate the important things outside of treatment: work, time with family, self-care.

"We want to help find the best way to realign your schedule to accommodate radiation. There’s a reason why you’re doing radiation: to treat the cancer and prolong your life. Our goal is that treatment doesn’t stall your life and that you can still do the things you love and enjoy doing. See how you can reschedule yourself to get a good balance for getting through treatment."

“I like to ask, ‘What are your plans this week/weekend?’ ‘What do you look forward to doing after radiation is completed?’ I want to know what is important in your life and what you can focus on outside of treatment to help push through those difficult days,” says Winner.

Skin irritation and other side effects can have an emotional impact too, she says. “Skin side effects can be painful and difficult to look at, and seeing the effects throughout the day can be a constant reminder. It can feel like losing your sense of self. I invite people to talk about what it feels like for them and remind them that the skin issues will subside, and that this is just another part of their journey. It’s a universal experience: You’re not alone with what you are experiencing, and what you’re feeling is okay, whether you’re frustrated, sad, or angry. There’s no wrong way to react.”

If you’re feeling overwhelmed, connecting with your clinic social worker can help. Together, you can explore coping skills to help manage those feelings of frustration, anger, or sadness. Your social worker can also connect you with support groups and programs through the cancer center and in the community. Additionally, your social worker can provide a supportive, listening ear when needed and connect you with a therapist for more long-term support. A cancer diagnosis and treatment are challenging, both physically and emotionally, but you don’t have to go through it alone.


Related resources


Reviewed and updated: January 10, 2022

Reviewed by: Neil K. Taunk, MD, MSCTS


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