Radiation therapy for breast cancer

Radiation therapyinfo-icon, also known as radiotherapyinfo-icon, directs high-energy x-rays to a specific part of the body to kill cancer cells. For early-stage breast cancerinfo-icon, there are two general types of radiationinfo-icon therapies: whole breast radiation and partial breast radiation. Radiation and other treatments focused on a certain part of the body are often called local therapyinfo-icon because they are “local” to one part of the body.

Radiation therapy can be very effective in lowering the risk of early- and advanced-stageinfo-icon cancer coming back. This includes diagnoses like DCISinfo-icon, early-stage invasive breast cancerinfo-icon, lymphinfo-icon-node positive disease, and inflammatory breast cancerinfo-icon.  

We know that radiation therapy is very effective for reducing the risk of breast cancer recurrenceinfo-icon. According to Neil Taunk, MD, MSCTS, “After surgeryinfo-icon and radiation therapy, recurrences in the breast, chest, or lymph nodes after targeted radiation to those areas are quite uncommon. However, the rate of recurrence can vary based on characteristics such as the tumorinfo-icon type, surgery, lymph nodeinfo-icon involvement, and use of systemic therapyinfo-icon.”

In early-stage breast cancer, radiation may be given to part of your breast or your whole breast. After mastectomyinfo-icon or in lymph-node positive disease, treatment may also include radiation to the chest wallinfo-icon, the area above your collarbone, or under your arm. It’s usually given after surgery to remove the cancer. If chemotherapyinfo-icon and radiation therapy are recommended, chemotherapy is typically completed before radiation.

In metastaticinfo-icon breast cancer, radiation therapy can slow cancer growth or relieve pain from breast cancer that has spread to other parts of the body, like the bones or the brain.

While radiation therapy can kill cancer cells or slow their ability to grow, radiation can also damage healthy cells. Common side effects of radiation therapy can include redness and peeling of the skin, breast swelling, and fatigueinfo-icon

On this page, we’ll explain the different kinds of radiation therapy available for breast cancer treatment, when radiation is typically recommended, and what you can expect with treatment.

Types of radiation therapy for breast cancer

The two main types of radiation therapy for breast cancer are external beam radiation therapy (EBRT) and internal radiation, or brachytherapyinfo-icon.

  • External beam radiation is the most common type of radiation therapy used to treat breast cancer. From outside the body, a large machine called a linear acceleratorinfo-icon directs high-energy x-rays into the area affected by the cancer.
  • External beam radiation therapy can be directed at the entire breast (whole breast radiation) or part of the breast (partial breast radiation).
  • Partial breast radiation focuses mainly on the area where the cancer was first found.
  • Partial breast radiation can also be given internally using a type of treatment called brachytherapy. In this procedure, a surgeoninfo-icon places a tiny balloon or hollow, flexible tubes called catheters in the area where the tumor was. In most cases, brachytherapy radiation is given on an outpatientinfo-icon basis, twice a day for a week. Each treatment may take up to half an hour. When you complete treatment, the surgeon removes the catheters or balloon. Brachytherapy is less available than external beam radiation.
  • Another form of partial breast radiation is called intraoperative radiation therapyinfo-icon (IORT). This procedure takes place during lumpectomyinfo-icon surgery, or sometimes in a second procedure after lumpectomy. After doctors remove the tumor, one large doseinfo-icon of radiation is given to the surgical area before the incisioninfo-icon is closed. IORT is still being studied and is not available at many hospitals. Visit the IORT page to learn more.

Schedules for whole and partial breast radiation can vary. Usually, whole breast radiation treatment is given at an outpatient center 5 days a week for 3 to 5 weeks, but shorter schedules may be an option in some cases. Each treatment takes about 15 minutes. Short courses of external beam partial radiation may also be available. To learn more about timing and schedules, visit the Radiation Schedules for Breast Cancer Treatment page.

When is radiation therapy used to treat breast cancer?

Radiation therapy is given

  • after lumpectomy surgery to remove a breast tumor, to kill any cancer cells that might remain in the body after surgery
  • after mastectomy if the cancer was over 5 centimeters across, was in the skin or muscle, or was in lymph nodes
  • to treat areas of metastatic breast cancer spread to other parts of the body, such as the brain or the bones

After lumpectomy, almost everyone benefits from radiation therapy to some degree, so it’s almost always recommended. Research shows that lumpectomy plus whole breast radiation can greatly reduce the risk of recurrence when compared with lumpectomy alone. Some emerging research suggests that it may be safe for some groups with low recurrence risk, after an informed discussion with their radiation oncologistinfo-icon, to skip radiation after lumpectomy. It’s important to talk with your healthcare team about your risk of recurrence and the most effective plan for keeping your risk as low as it can be.

With a mastectomy, you may not need radiation. Your doctor may recommend radiation therapy to reduce the chance of the cancer coming back in your skin, the chest wall, or nearby lymph nodes if

  • the primary tumorinfo-icon is larger than 5 centimeters across
  • the cancer is in the lymph nodes under your arm
  • the cancer has grown into the skin or chest wall muscle under the breast
  • you have locally advanced or inflammatory breast cancer

In metastatic breast cancer, radiation therapy can be used to treat cancer that has spread to certain areas, such as the brain. Radiation therapy can help with pain relief (with bone pain, for example) and reducing the risk of cancer-related complications.

In some situations, radiation therapy is not recommended. Radiation therapy is not safe for pregnant women at any time during pregnancy because of the risk radiation poses to the developing baby. If you are pregnant and have been diagnosed with breast cancer, talk with your healthcare team about your treatment options.

If your job, family obligations, or other life situations make it difficult to come to radiation treatments, it’s important to let your doctors know. Ask if adjustments can be made in the schedule, or there are other options available to you. Your doctor may be able to offer a different schedule that allows a slightly higher dose of radiation in a shorter timeframe.

What to expect before radiation therapy treatment

If your doctor has recommended radiation therapy for you, here are some things you can expect as you prepare to start treatment.

Informed consentinfo-icon

You will likely be asked to sign an agreement between yourself and your healthcare team that grants them permission to treat you. This ensures that you’ve had a chance to ask questions and your doctor has given you all the radiation therapy information you need, including the risks and benefits of the treatment. This process is called informed consent. Informed consent protects your right to have regular communication with and information from your healthcare team.

Treatment planning

Before you start radiation therapy treatment, you and your healthcare team will decide on a treatment schedule. The typical schedule for standard whole breast radiation treatment is once a day, 5 days a week, for 3 to 5 weeks. Partial breast radiation may mean a shorter course of treatment in some cases. You can learn more about schedules on the Radiation Schedules for Breast Cancer Treatment page.

Treatment planning also means understanding costs and your health insurance coverage. In the Job and Financial Concerns section, you can learn about health insurance, work accommodations after a breast cancer diagnosisinfo-icon, and more. One way to cut costs, have access to new treatment methods, and potentially help others diagnosed with breast cancer in the future is to participate in a clinical trialinfo-icon. Visit the Clinical Trials page to learn more.  

Radiation simulationinfo-icon

Before you start receiving actual radiation treatments, you’ll have a planning session called a simulation. This is something like a treatment dress rehearsal. On that day, you’ll do everything you would on a normal treatment day, except receive the radiation. This allows the radiation oncologist and radiation therapists to get familiar with the treatment plan and make adjustments, if needed. Your team will position you on the treatment table and find the exact area on your body where the radiation will be targeted. You may be asked to hold your breath, put your arms over your head, or position your head a certain way. This helps you and your team identify how your body will be positioned for every treatment.

In some cases your team may recommend using a technique called deep inspiration breath hold (DIBH) to reduce the risk of radiation reaching the heart area. If this has been recommended for you, you will be coached on how to practice DIBH before and during the simulation session.

During simulation, your radiation team will determine where small tattoos — dots of permanent ink about the size of a small freckle — will be placed on your body. The tattoos help make sure the exact same area is always radiated. If more radiation is needed later, the tattoos ensure that doctors know you’ve had previous radiation there, because radiating the same area more than once is not usually recommended.

Many women say that getting the tattoos feels similar to a pin prick. In general, a person may receive 4 to 8 tattoos. While these tattoos are permanent, they are so small that they’re not usually very visible to most people looking at you.

Several days to a week after the simulation session, you will begin treatment.

What to expect after receiving radiation

Once you’ve started radiation therapy, you may begin to notice side effects such as skin redness and irritation (like a sunburn), breast swelling, and as treatment continues, fatigue.

Skin side effects often heal several weeks after you finish treatment. Changes to the color of your skin may take longer to heal, but your radiation oncologist will monitor your skin in the weeks after you complete treatment.

Visit the Breast Radiation Side Effects page for tips on managing these and other temporary changes.

Additional resources

Below, you can find more articles about radiation therapy for breast cancer, stories from others who’ve been there, and downloadable resources to support you as you make important decisions about your care.

Related pages

Related news & opinion

From the blog

 Free downloadable resources

How Do I Know If I Need Radiation?

At some point after your diagnosisinfo-icon, you may meet with a radiation oncologistinfo-icon, a doctor with special training in treating cancer with radiationinfo-icon.

Your doctor will talk with you about your medical history, your breast cancer diagnosis and any other illnesses you may have. Then your doctor will explain whether radiation therapyinfo-icon plays a role in your treatment plan.

Almost everyone who has a lumpectomy benefits from radiation therapy to some degree, so it’s almost always recommended after that surgeryinfo-icon.

If you have a mastectomy, you may not need radiation. Your doctor may recommend radiation therapy to reduce the chance of the cancer coming back in your skin or the chest wallinfo-icon or nearby lymphinfo-icon nodes if:

  • the primary tumorinfo-icon is larger than 5 centimeters across
  • the cancer involves the lymph nodes under your arm
  • the cancer has grown into the skin or chest wall muscle under the breast
  • you have locally advanced or inflammatory breast cancer

What Happens at Treatment?

Radiationinfo-icon can be given in different ways. Usually, you will receive it from outside your body by an external beam, but it can also be given from inside the body via a radioactiveinfo-icon implantinfo-icon. Radiation isn’t painful. You won’t feel the beam going into your body.

Before you begin radiation therapyinfo-icon, your radiation oncologistinfo-icon plans your treatments. This plan ensures the radiation targets the exact area of the cancer, without causing too much harm to healthy tissues nearby.

To kill cancer cells, radiation treatment must be very precise. Your doctor will give you a CAT or CT scaninfo-icon to find the right places on your body to radiate. This special x-ray takes pictures of the inside of your breast from many different angles.

Your radiation oncologist then uses the pictures to choose where small tattoos, dots of permanent ink about the size of a small freckle, will be placed on your body. The tattoos help make sure the exact same spot is always radiated. Many women say that getting the tattoos feels similar to a pin prick.

Often, your radiation oncologist will ask you to complete a “dry run,” a treatment dress rehearsal. On that day you’ll do everything you would on a normal treatment day except receive the radiation. You may be asked to hold your breath, put your arms over your head or position your head a certain way. This rehearsal allows the radiation oncologist and radiation therapists to get familiar with the treatment plan and make adjustments, if needed. Several days to a week later, you will begin treatment.

How long radiation treatment takes depends on the kind of treatment you receive. Because there are different types of radiation for breast cancer, ask your doctors to explain why they recommend a certain kind for you.

Side Effects of Radiation Therapy

Radiationinfo-icon itself is not painful but it has some side effects. Because it is a local treatment, radiation treatment may not cause as many or as severe side effects as other whole-body therapies. That’s because most side effects are generally limited to the treatment area.

FatigueRadiation does not hurt, but sometimes it can make you feel more tired than usual. Radiation treatments and their effects build up in your body over time, so as your treatments go on, your fatigueinfo-icon may increase.

Expect to feel more tired in the last few weeks of treatment. Plan time for naps and resting. Gentle exercise such as walking, keeping a healthy diet and resting when you feel tired can help.

Skin ReactionsThe skin on or near the radiated area may become dry, red, scaly, itchy and sore. Your skin may also burn, peel or blister, like a sunburn. Remember not to pick or scratch, as this can lead to infectioninfo-icon and delay treatment.

Your radiation oncologistinfo-icon can help you manage skin reactions by providing skin care tips, prescribing medicines or recommending salves, such as pure aloe. Avoid using products that have alcohol, as it can dry the skin and cause a burning feeling. If possible, wear loose cotton clothes to keep your skin from rubbing too much against your clothes.

Skin side effects often heal several weeks after you finish radiation therapyinfo-icon. Changes to the color of your skin may take longer to heal, but your radiation oncologist will monitor your skin for weeks after you complete treatment.

Other Side EffectsRadiation can increase the risk of lymphedema if the lymphinfo-icon nodes under your arm or around your collarbone are radiated. The risk is higher if lymph nodes were removed from the armpit region and if you are overweightinfo-icon.

Long-term side effects may include swelling of the breast (edemainfo-icon), a hardening or thickening of the breast tissueinfo-icon (fibrosis), the treated area becoming red (telangiectasia) and restricted arm or shoulder movement.  

Rare side effects may include:

  • Rib fracture
  • Heart problems (if treated on the left side)
  • Inflammationinfo-icon of the lungs
  • Damage of nerves in the chest causing pain, tingling and weakness in the affected hand and arm
  • A second cancer, such as sarcoma

Discuss all the benefits and possible side effects of radiation therapy, both short- and long-term, with your doctor. Be sure to also communicate any issues or concerns you have during treatment.

Updated 
July 14, 2021
Reviewed By: 
Neil K. Taunk;  
MD;  
MSCTS