Brachytherapy for Breast Cancer

Author: Courtney Misher, MPH, BS R.T.(T)
Last Reviewed: March 10, 2023

What is Brachytherapy?

Brachytherapy is a form of radiation treatment where a source of radiation is put inside your body (internal radiation). This can be an option for certain women after lumpectomy, depending on the size and location of the cancer. Brachytherapy allows a higher dose of radiation to go directly to the area where the tumor was before surgery. It can also be used to give an extra boost dose of radiation after whole breast radiation.

Brachytherapy is one way to deliver accelerated partial-breast radiation (APBI). APBI gives a larger dose of radiation over a shorter period. It only gives radiation to the breast area where the cancer was, not the whole breast. Two types of brachytherapy are used for breast cancer, intracavitary and interstitial.

Intracavitary Brachytherapy (Balloon Internal Radiation or MammoSite)

Incision in breast where MammoSite balloon is inserted.

This is the most common type of brachytherapy used for breast cancer. It targets the area where cancer is most likely to come back. This procedure uses a tube (catheter) with a balloon at the tip that is placed in the breast where the cancer was. The tube comes out of the skin through a small hole. This device can be placed either during lumpectomy surgery or afterward as an outpatient (no overnight stay required) procedure.

What can I expect during intracavitary brachytherapy treatment?

CAT Scan images illustrating MammoSite balloon in treatment position with dummy seeds (non-radioactive seeds).

The deflated balloon is placed into the space in the breast where the tumor was removed from. The balloon is filled with saline (salt water) until it fits comfortably in the space. The opposite end of the tube stays outside of the breast. Most people do not have discomfort while the balloon is being placed or filled with saline.

Once the balloon has been placed, a CT scan of the breast is done and used to make the treatment plan. The plan is made specifically for each patient. During the treatment, a machine (called an afterloader) places radioactive seeds into the balloon through the tube for about 5 to 10 minutes. Typically, 2 treatments are given per day at least 6 hours apart. The treatments are given over 5 days for a total of 10 treatments. After your treatments, are done the tube and the balloon is removed through the existing hole in the skin.

Interstitial Needle-Catheter Brachytherapy (Multi-catheter Internal Radiation)

This procedure also uses radioactive seeds to deliver radiation directly to the area where the cancer was. The seeds are placed in small tubes (catheters) that are sewn under the skin. The tubes stick out through little holes in the skin. This type of treatment can be given as high-dose radiation or low-dose radiation.

  • High-Dose Radiation (HDR):High-dose radiation is more common and is given as an outpatient procedure. Each appointment is about 1 hour long. The actual treatment will only last about 10 minutes. It is common for this type of procedure to be done 2 times a day for 5 days for a total of 10 treatments. Once all the treatments have been done, the catheter and stitches are removed.
  • Low-Dose Radiation (LDR): Less often, low-dose radiation is used. This treatment is given over several hours or a few days. This treatment is done as an inpatient (stay overnight in the hospital) procedure. During this time, you will slowly be receiving the radiation. You will have radioactive seeds inside you during this time. Once treatment is done, the seeds, stitches, and catheters are removed.

Side Effects of Brachytherapy

Some side effects that are possible with brachytherapy are:

  • Bruising or redness at the treatment site.
  • Pain in the breast.
  • Infection.
  • Fatty tissue damage in the breast.
  • Fluid collection in the breast.
  • Fracture of the ribs, which is rare.

Is brachytherapy a treatment option for me?

Brachytherapy is not a treatment option for all breast cancer cases. It may be an option if you meet certain criteria:

  • You are 45 years or older with ductal carcinoma in situ (DCIS) or early-stage invasive breast cancer.
  • Have had a lumpectomy.
  • Your tumor is 3 cm or smaller in size.
  • Your cancer is hormone receptor (HR) positive or hormone receptor-negative.
  • You do not have cancer in the lymph nodes.
  • You do not have cancer cells in the small blood vessels or lymph vessels (lymphovascular space invasion).
  • You do not have cancer in healthy tissue where the cancer was removed (negative or clear margins).

Advantages and Disadvantages of Brachytherapy Over External Radiation

Advantages of brachytherapy:

  • It limits the amount of radiation to surrounding normal tissue and structures including the heart and lungs.
  • Treatment duration is much shorter – 5 days instead of many weeks.
  • Radiation is focused on the area where the cancer is most likely to return. Less radiation to the normal tissue causes fewer side effects.
  • In early-stage cancer, brachytherapy has been shown to be very good at preventing cancer from coming back after surgery.

Disadvantages of brachytherapy:

  • It is used after a lumpectomy. If you had a mastectomy, it likely will not be an option.
  • The look and feel of the breast after treatment may not be as good with brachytherapy compared to external radiation.
  • It is not available at all hospitals or oncology clinics.
  • In some cases, the procedure is done as an inpatient procedure so you will need to stay at the hospital.

Choosing Your Treatment

Not all breast cancers can be treated with brachytherapy. You should talk about your options with your providers. It is important to talk about the side effects of each treatment and what option is best for you.

Kauer-Dorner D., Berger D.: The Role of Brachytherapy in the Treatment of Breast Cancer. Breast Care 2018; 13:157-161. Doi: 10.1159/000489638. Retrieved from

Radiation for Breast Cancer. Breast Cancer Treatment. (2021, October 27). Retrieved February 27, 2023, from

Shah, C., Vicini, F., Shaitelman, S. F., Hepel, J., Keisch, M., Arthur, D., Khan, A. J., Kuske, R., Patel, R., & Wazer, D. E. (2018). The American Brachytherapy Society consensus statement for accelerated partial-breast irradiation. Brachytherapy, 17(1), 154–170.

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