Radiation Therapy for Breast Cancer

Radiation therapy for breast cancer kills cancerous cells in tumors. People who have breast cancer surgery often receive radiation therapy afterward to eliminate cancer cells that remain after surgery. Radiation therapy for breast cancer can cause short-term and long-term side effects.


Radiation therapy for breast cancer can cause short-term side effects and long-term side effects.
Side effects from radiation therapy for breast cancer may last for weeks or months after you finish treatment.

What is radiation therapy for breast cancer?

Radiation therapy for breast cancer uses high-powered X-rays to kill or damage cancerous cells in your breast. Breast surgeons/surgical oncologists (cancer specialists) often do breast cancer surgery to remove tumors. Then, radiation oncologists oversee radiation therapy to eliminate remaining cancerous cells. People with metastatic breast cancer may have this treatment to ease breast cancer symptoms or symptoms from other areas of their bodies.


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Types of radiation therapy for breast cancer

There are different ways to receive radiation therapy. Your radiation oncologist will choose the best method based on the cancer location, type and other factors.

Types of radiation therapy for breast cancer include:

  • External beam radiation therapy (EBRT): In this treatment, a machine called a linear accelerator sends beams of high-energy radiation to your breast. Most people have this treatment five days a week for one to six weeks. EBRT may include intensity-modulated radiation therapy (IMRT) or stereotactic body radiation therapy (SBRT).
  • Brachytherapy: This is internal radiation therapy. A radiation oncologist uses a catheter to place a tiny radioactive seed into the tumor site. The seed gives off radiation for several minutes before your provider removes it. You receive two treatments every day for five days.
  • Intraoperative radiation therapy (IORT):Your surgeon does this treatment in the operating room after your surgeon removes the tumor in your breast and before they close the surgical site. They deliver a high dose of radiation to the tumor area of the exposed breast tissue.

Procedure Details

What happens at my first appointment for radiation therapy for breast cancer?

Your first appointment is a planning session and a chance for your radiation oncology team to explain processes and answer your questions. The team will:

  • Discuss your treatment schedule — how often you’ll receive radiation — and what you can expect during treatment. For example, radiation therapy sessions typically last 30 to 45 minutes. Your actual treatment takes place in two-to-three-minute increments during a 15-minute period.
  • Explain the process, including how radiation is delivered, where the team will be during treatment and anything you can’t do during treatment, like move around.
  • Demonstrate techniques that help protect your heart and lungs from radiation exposure. For example, they may show you how to do deep inspiratory breath holds. This involves taking and holding a deep breath at specific times during treatment. This technique helps protect your heart and lungs during treatment.
  • Recommend things you can do before treatment so you’re as comfortable as possible. For example, they may recommend you wear a loose-fitting top to your treatments that won’t brush up against your breast skin.
  • Discuss potential side effects and ways to manage them. They may suggest palliative care, which helps people cope with disease symptoms and treatment side effects.

Knowing what to expect may help you make plans and coordinate your personal activities like work and other obligations.

The planning session also involves a simulation. In simulations, your radiation oncology team uses a computed tomography (CT) scan to map out the area on your breast they need to treat. Simulation may take an hour or more.

During the simulation, a team member will:

  • Carefully position your body in an immobilization device on the treatment table. This device helps you stay in the correct position for all treatments. Your radiation therapy team will do their best to help you feel comfortable.
  • Show you how to use techniques that protect your heart and lungs from radiation.
  • Use a tattoo device to mark the corners of the part of your breast to be treated. These marks help your team align the radiation treatment in the same way each time. The marks are about the size of a freckle. They can be permanent or temporary. (You should discuss your preferences with your radiation oncologist.)

What happens during radiation therapy for breast cancer?

When you arrive for treatment, a team member will greet you and give you a medical gown to wear during treatment. Next, they’ll:

  • Escort you to the treatment room.
  • Help you up on the treatment table. Most people lie on their backs during treatment, but sometimes, people lie on their stomachs. How you lie depends on the treatment plan. You’ll place an arm above your head (the arm on the same side as the breast with cancer).
  • Help you get into position in the immobilization device. If you’re receiving radiation therapy after a mastectomy, your provider may put a flat piece of wet towel or rubber on the part of your breast that’s being treated. This helps increase the amount of radiation sent to the skin.
  • Next, they’ll line up the linear accelerator with the first area to be treated. As your team will have explained, they’ll leave the room during treatment, but will still be able to see you and hear you.
  • They’ll turn on the machine. You’ll hear a whirring noise, but radiation beams are invisible, and you won’t feel anything.
  • Once treatment is done, your team will help you up from the treatment table.


What are treatment side effects?

Typically, radiation therapy doesn’t cause immediate side effects, but you may have short-term and long-term reactions.

Short-term side effects may include:

  • Fatigue: Most people have mild fatigue that starts during treatment and goes away a few weeks after treatment is finished.
  • Skin irritation: Your skin may feel very dry and notice some skin flakes. Your skin may peel. Some people develop moist desquamation, a skin condition that often occurs in the fold under your breast or the fold between your breast and your arm. Your skin may blister and peel.
  • Changes in skin color: If you have fair skin, your skin may look like you have sunburn. If you have dark skin, you may notice your skin appears darker than usual.
  • Breast pain: Some people have dull pain or sharp shooting pains in their breast. The pain typically comes and goes. Your nipples or breast may feel sore.

Long-term side effects may include:

  • Spider veins (telangiectasias): This is normal and not something you should worry about.
  • Change in breast size: Your breast may become larger or smaller.
  • Lymphedema: Some people who have radiation therapy to the lymph node areas for breast cancer have swelling that affects the arm on the same side as the breast cancer.
  • Persistent fatigue: Some people feel noticeably tired for weeks or months after they’re done with treatment.

Unlike some forms of chemotherapy, most people don’t lose their hair from their heads during radiation therapy, but they may lose armpit hair.

Risks / Benefits

What are the benefits of radiation therapy for breast cancer?

Radiation therapy is an effective way to target breast cancer tumors without damaging nearby tissues. Research shows breast cancer is less likely to come back (recur) in people with early-stage breast cancer who have radiation therapy after surgery. According to the American Society of Clinical Oncology, less than 5% of people have recurrent breast cancer 10 years after surgery and radiation therapy.


What are risks or complications of this treatment?

Rarely, radiation therapy for breast cancer causes complications, like issues that affect your chest. Potential complications include:

Recovery and Outlook

How can I take care of myself during and after this treatment?

Radiation therapy can make your skin feel very tender, itchy and painful. It may affect your appetite and make you feel very tired. Here are some suggestions to help you through treatment:

  • Wear loose-fitting cotton clothes. Tight-fitting bras and clothes may rub against your breast and make your breast hurt or feel sore.
  • Baby your tender, itchy skin. Wash your skin with gentle soap and warm water. Ask your radiation therapy team to recommend creams or lotions that will ease treatment side effects without damaging your skin.
  • Get some rest. Radiation therapy may make you feel very tired, especially during the last few treatment sessions. You may need to build rest time into your daily schedule.
  • Eat well. A diet of healthy grains, fruits, vegetables, lean protein and low-fat dairy will help you stay strong through treatment.
  • Get some exercise. Regular gentle exercise, like a 30-minute daily walk, will help you manage fatigue.

Will I be able to work and manage other obligations during treatment?

That depends on your situation. You’ll probably feel OK when you first start treatment and then notice you have less energy and feel more tired as treatment continues.

When To Call the Doctor

When should I call my healthcare provider?

Let your provider know anytime you have side effects that are more severe than you expected.

What questions should I ask my provider?

You may want to ask the following questions when you meet with your radiation therapy team:

  • What type of radiation therapy is recommended for me? Why?
  • How long will it take to have this treatment? How often will I have radiation therapy?
  • What short-term side effects can I expect during radiation therapy?
  • What can be done to relieve side effects I experience?
  • Who should I talk with about any side effects I experience? How soon?
  • How will this treatment affect my daily life? Will I be able to work, exercise and perform my usual activities?
  • What are the possible long-term side effects of this type of radiation therapy?
  • If I’m very worried or anxious about having this treatment, who can I talk with?
  • When will we know if this treatment was successful? How?

A note from Cleveland Clinic

Radiation therapy for breast cancer is a common, effective treatment for early-stage and more advanced breast cancer. It may also help ease symptoms of metastatic breast cancer. Studies show this treatment keeps breast cancer from coming back. The treatment may cause short-term and long-term side effects. If you have breast cancer, talk to your healthcare providers about radiation therapy. They’ll be glad to explain the treatment and how it may fit into your plan for conquering breast cancer.

Medically Reviewed

Last reviewed on 08/18/2023.

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