Radiation for Breast Cancer

Radiation therapy is treatment with high-energy rays (or particles) that destroy cancer cells. Some women with breast cancer will need radiation, in addition to other treatments. Radiation therapy is used in several situations:

  • After breast-conserving surgery (BCS), to help lower the chance that the cancer will come back in the same breast or nearby lymph nodes.
  • After a mastectomy, especially if the cancer was larger than 5 cm (about 2 inches), if cancer is found in many lymph nodes, or if certain surgical margins have cancer such as the skin or muscle.
  • If cancer has spread to other parts of the body, such as the bones or brain.

The main types of radiation therapy that can be used to treat breast cancer are external beam radiation therapy (EBRT) and brachytherapy.

External beam radiation

This is the most common type of radiation therapy for women with breast cancer. A machine outside the body focuses the radiation on the area affected by the cancer.

Which areas need radiation depends on whether you had a mastectomy or breast-conserving surgery (BCS) and whether or not the cancer has reached nearby lymph nodes.

  • If you had a mastectomy and no lymph nodes had cancer cells, radiation is focused on the chest wall, the mastectomy scar, and the places where any drains exited the body after surgery.
  • If you had BCS, you will most likely have radiation to the entire breast (called whole breast radiation), and an extra boost of radiation to the area in the breast where the cancer was removed (called the tumor bed) to help prevent it from coming back in that area. The boost is often given after the treatments to the whole breast have ended. It uses the same machine, with lower amounts of radiation aimed at the tumor bed. Most women don’t notice different side effects from boost radiation than from whole breast radiation.
  • If cancer was found in the lymph nodes under the arm (axillary lymph nodes), this area may be given radiation, as well. In some cases, the area treated might also include the nodes above the collarbone (supraclavicular lymph nodes) and the nodes beneath the breast bone in the center of the chest (internal mammary lymph nodes).

When will I get radiation therapy?

If you will need external radiation therapy after surgery, it is usually not started until your surgery site has healed, which often takes a month or longer. If you are getting chemotherapy as well, radiation treatments are usually delayed until chemotherapy is complete.

Preparing for external beam radiation therapy

Before your treatment starts, the radiation team will carefully figure out the correct angles for aiming the radiation beams and the proper dose of radiation. They will make some ink marks or small tattoos on your skin to focus the radiation on the right area. Ask your health care team if the marks they use will be permanent.

External radiation therapy is much like getting an x-ray, but the radiation is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, but the setup time—getting you into place for treatment—usually takes longer.

Types and schedules of external beam radiation for breast cancer

Whole breast radiation

  • The standard schedule for getting whole breast radiation is 5 days a week (Monday through Friday) for about 6 to 7 weeks.
  • Another option is hypofractionated radiation therapy where the radiation is also given to the whole breast, but in larger daily doses (Monday through Friday) using fewer treatments (typically for only 3 to 4 weeks). In women treated with breast-conserving surgery (BCS) and without cancer spread to underarm lymph nodes, this schedule has been shown to be just as good at keeping the cancer from coming back in the same breast as giving the radiation over longer periods of time. It might also lead to fewer short-term side effects.

Accelerated partial breast irradiation

In select women, some doctors are using accelerated partial breast irradiation (APBI) to give larger doses over a shorter time to only one part of the breast compared to the entire breast. Since more research is needed to know if these newer methods will have the same long-term results as standard radiation, not all doctors use them. There are several different types of accelerated partial breast irradiation:

  • Intraoperative radiation therapy (IORT): In this approach, a single large dose of radiation is given to the area where the tumor was removed (tumor bed) in the operating room right after BCS (before the breast incision is closed). IORT requires special equipment and is not widely available.
  • 3D-conformal radiotherapy (3D-CRT): In this technique, the radiation is given with special machines so that it is better aimed at the tumor bed. This spares more of the healthy breast. Treatments are given twice a day for 5 days.
  • Intensity-modulated radiotherapy (IMRT): IMRT is like 3D-CRT, but it also changes the strength of some of the beams in certain areas. This gets stronger doses to certain parts of the tumor bed and helps lessen damage to nearby normal body tissues.
  • Brachytherapy: See brachytherapy below.

Women who are interested in these approaches may want to ask their doctor about taking part in clinical trials of accelerated partial breast irradiation.

Chest wall radiation

If you had a mastectomy and none of the lymph nodes had cancer, radiation will be given to the entire chest wall, the mastectomy scar, and the areas of any surgical drains. It is typically given daily 5 days a week for 6 weeks.

Lymph node radiation

Whether or not you have had BCS or a mastectomy, if cancer was found in the lymph nodes under the arm (axillary lymph nodes), this area may be given radiation. In certain cases, the lymph nodes above the collarbone (supraclavicular lymph nodes) and behind the breast bone in the center of the chest (internal mammary lymph nodes) will also receive radiation along with the underarm nodes. It is typically given daily 5 days a week for 6 weeks at the same time as the radiation to the breast or chest wall is given.

Possible side effects of external radiation

The main short-term side effects of external beam radiation therapy to the breast are:

  • Swelling in the breast
  • Skin changes in the treated area similar to a sunburn (redness, skin peeling, darkening of the skin)
  • Fatigue

Your health care team may advise you to avoid exposing the treated skin to the sun because it could make the skin changes worse. Most skin changes get better within a few months. Changes to the breast tissue usually go away in 6 to 12 months, but it can take longer.

External beam radiation therapy can also cause side effects later on:

  • Some women may find that radiation therapy causes the breast to become smaller and firmer.
  • Radiation may affect your options for breast reconstruction later on. It can also raise the risk of problems with appearance and healing if it’s given after reconstruction, especially tissue flap procedures.
  • Women who have had breast radiation may have problems breastfeeding.
  • Radiation to the breast can sometimes damage some of the nerves to the arm. This is called brachial plexopathy and can lead to numbness, pain, and weakness in the shoulder, arm, and hand.
  • Radiation to the underarm lymph nodes might cause lymphedema, a type of pain and swelling in the arm or chest.
  • In rare cases, radiation therapy may weaken the ribs, which could lead to a fracture.
  • In the past, parts of the lungs and heart were more likely to get some radiation, which could lead to long-term damage of these organs in some women. Modern radiation therapy equipment better focuses the radiation beams, so these problems are rare today.
  • A very rare complication of radiation to the breast is the development of another cancer called an angiosarcoma.

Brachytherapy

Brachytherapy, also known as internal radiation, is another way to deliver radiation therapy. Instead of aiming radiation beams from outside the body, a device containing radioactive seeds or pellets is placed into the breast tissue for a short time in the area where the cancer had been removed (tumor bed).

For certain women who had breast-conserving surgery (BCS), brachytherapy can be used by itself (instead of radiation to the whole breast) as a form of accelerated partial breast irradiation. Tumor size, location, and other factors may limit who can get brachytherapy.

Types of brachytherapy

  • Intracavitary brachytherapy: This is the most common type of brachytherapy for women with breast cancer. A device is put into the space left from BCS and is left there until treatment is complete. There are several different devices available, most of which require surgical training for proper placement. They all go into the breast as a small catheter (tube). The end of the device inside the breast is then expanded like a balloon so that it stays securely in place for the entire treatment. The other end of the catheter sticks out of the breast. For each treatment, one or more sources of radiation (often pellets) are placed down through the tube and into the device for a short time and then removed. Treatments are typically given twice a day for 5 days as an outpatient. After the last treatment, the device is deflated and removed.
  • Interstitial brachytherapy: In this approach, several small, hollow tubes called catheters are inserted into the breast around the area where the cancer was removed and are left in place for several days. Radioactive pellets are inserted into the catheters for short periods of time each day and then removed. This method of brachytherapy has been around longer (and has more evidence to support it), but it is not used as much.

Early studies of intracavitary brachytherapy as the only radiation after BCS have had promising results as far as having at least equal cancer control compared with standard whole breast radiation, but may have more complications including poor cosmetic results. Studies of this treatment are being done and more follow-up is needed.   

Possible side effects of intracavitary brachytherapy

As with external beam radiation, intracavitary brachytherapy can have side effects, including:

  • Redness and/or bruising at the treatment site
  • Breast pain
  • Infection
  • Damage to fatty tissue in the breast
  • Weakness and fracture of the ribs in rare cases
  • Fluid collecting in the breast (seroma)

More information about radiation therapy

To learn more about how radiation is used to treat cancer, see Radiation Therapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: September 18, 2019 Last Revised: September 18, 2019

 

 

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