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Radiation Therapy for Breast Cancer

Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. In some cases, women with breast cancer will need radiation therapy, often in addition to other breast cancer treatments.

There are two main types of radiation therapy that are used to treat breast cancer: external beam and internal radiation therapy. The type of radiation therapy that you may have depends on a variety of factors, which may include your age, what type of surgery you had, whether your cancer has spread to other areas of your body (metastasized), and the stage of your breast cancer.

External Beam Radiation Therapy

External beam radiation therapy comes from a machine that aims radiation at your cancer from outside the body. The machine does not touch you, but moves around you, sending radiation to a part of your body from many directions.

External radiation is the most common type of radiation therapy used for breast cancer and is considered a local treatment. This means it treats the tumor without affecting the rest of the body.

Internal Radiation Therapy: HDR Brachytherapy

High-dose rate (HDR) brachytherapy is a type of internal radiation therapy that is often used to treat breast cancer, typically after a lumpectomy. The treatment delivers radiation from implants placed inside the breast versus an external beam pointed at the breast. These small pieces of radioactive pellets, called seeds, are placed in the breast around where the cancer was through a surgically placed catheter (tube) for short periods of time each day and then removed.

There are two different types of brachytherapy used for breast cancer treatment: intracavitary brachytherapy and interstitial brachytherapy.

  1. Intracavitary brachytherapy, which is the most common type of brachytherapy for women with breast cancer, requires the surgical implantation of a single device into the area where the tumor was. This is the site of the lumpectomy. The device remains in place until treatment is complete
  2. Interstitial brachytherapy, on the other hand, involves implanting several catheters into the breast, near where they tumor was located, so that when the seeds are implanted they are pointed in the direction of the tumor cavity.

Rather than traditional breast cancer radiation, which typically requires at least six weeks, HDR brachytherapy treatment for breast cancer can be done in five days or less, which may result in a quicker recovery time.

When is radiation therapy a good fit for breast cancer treatment?

Radiation therapy can play an important role in treating all stages of breast cancer. Situations where radiation therapy for breast cancer might be an appropriate method may include:

  • After a lumpectomy (sometimes called breast-conserving surgery), to help reduce the chance of cancer recurrence in the breast or lymph nodes
  • After a mastectomy–especially if the cancer was greater than 5 cm (about 2 inches), or if cancer is found in the lymph nodes
  • If cancer has metastasized (spread to other parts of the body)

Radiation therapy for breast cancer is not for women who are pregnant, women who have already had radiation to that area of the body, or women who have a connective tissue disease, such as scleroderma or vasculitis.

When will radiation therapy be given during the breast cancer treatment process?

Your breast cancer specialist will determine the most effective order to administer various types of cancer treatment, including radiation therapy. provides this set of examples for various treatment sequences that involve radiation for breast cancer:

  • surgery → radiation → possible hormonal therapy
  • surgery → chemotherapy → radiation → possible hormonal therapy
  • chemotherapy, targeted therapy, or hormonal therapy → surgery → radiation → possible hormonal therapy

For patients who require chemotherapy, it is typically given before radiation. Chemotherapy can sometimes be done before surgery, also called neoadjuvant, and sometimes after surgery, also called adjuvant. Radiation then follows chemotherapy. They are not usually given at the same time. Depending on what chemotherapy you’re given, there can be anywhere from two weeks to a month between the last chemotherapy treatment and the start of radiation therapy.

Possible Side Effects of Breast Cancer Radiation

Radiation therapy can have either short-term or long-term side effects, depending on the type and the dose of radiation you receive. You might notice some changes in the area of the breast that was exposed.  

Some common, temporary reactions from radiation therapy may include:

  • Fatigue
  • Breast swelling and/or tenderness
  • Skin changes that resemble a sunburn, such as pain, redness, skin peeling, or darkening of the skin

These short-term side effects usually go away in 2 to 4 weeks. For some patients however, it may take longer.

Breast radiation therapy can also cause long-term side effects or side effects that don’t appear until after the completion of your radiation treatment, which may include:

  • Lymphedema, a type of pain and swelling in the arm or chest, if there is a need to treat the lymph nodes after a full axillary lymph node dissection. This is an uncommon problem with use of Sentinel Lymph Node Biopsy.
  • Firmness or shrinkage of the breast
  • Breastfeeding difficulties
  • Limited options for breast reconstruction

Long-term effects that are extremely rare may include weakening of the rib bones, organ damage (heart and lungs), and development of another cancer called an angiosarcoma.


AZ Oncology

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