Brachytherapy delivers radiation therapy directly to where cancer cells inside the breast are located. It may involve placing a radioactive source into the surgical site after the surgeon removes a breast lump. The radiation only reaches a small area around the surgical site. It does not treat the entire breast, which is why it is called "partial breast" radiation therapy or partial breast brachytherapy. The goal is to limit side effects of radiation to a smaller volume of normal tissue.

There are different types of brachytherapy. There are at least two ways to deliver radiation from inside the breast.

INTERSTITIAL BRACHYTHERAPY (IMB)

• Several small needles with tubes called catheters are placed through the skin into the tissues of the breast around the lumpectomy site. This is most often done 1 to 2 weeks after surgery.
• Mammography, ultrasound, or CT scans are used to place the radioactive material where it will work best to kill the cancer.
• The radioactive material is placed in the catheters and remains for 1 week.
• Sometimes the radiation can be delivered twice a day for 5 days by a remote-controlled machine.

INTRACAVITARY BRACHYTHERAPY (IBB)

• After breast lump removal, there is a cavity where the cancer was removed. A device that contains a silicone balloon and tube that has channels running through it can be inserted into this cavity. A few days after placement, radiation in the form of tiny radioactive pellets can go into the channels, delivering radiation from inside the balloon. This is often done two times a day for five days. Sometimes the catheter is placed during the first surgery while you are asleep.
• Ultrasound or CT scans are used to guide the exact placement of the radioactive material where it will work best to kill the cancer while protecting adjacent tissues.
• The catheter (balloon) remains in place for around 1 to 2 weeks and is removed at your health care provider's office. Stitches may be needed to close the hole from where the catheter is removed.

Brachytherapy may be given as "low dose" or "high dose."

• Those receiving low-dose treatment are kept in the hospital in a private room. Radiation is slowly delivered over hours to days.
• High-dose rate therapy (HDR brachytherapy) is provided as an outpatient using the remote machine, again usually over 5 or so days. Sometimes the treatment is delivered two times in a single day, separated by 4 to 6 hours between sessions. Each treatment takes about 15 to 20 minutes.

Other techniques include:

• Permanent breast seed implant (PBSI), in which radioactive seeds are individually inserted through a needle into the breast cavity several weeks after lumpectomy.
• Intraoperative radiation therapy is delivered in the operating room while you are asleep after breast tissue is removed. The treatment is completed in less than an hour. This uses a large x-ray machine inside the operating room.

Experts learned that certain cancers are most likely to return near the location of the original cancer. Therefore, in some cases, the whole breast may not need to receive radiation. Partial breast irradiation only treats some but not all of the breast, focusing on the area where the cancer is most likely to return, usually around the surgical cavity.

Breast brachytherapy helps prevent breast cancer from returning. The radiation therapy is given after lumpectomy (also called) a partial mastectomy. This approach is called adjuvant (additional) radiation therapy because it is adding a treatment beyond surgery.

Because these techniques are not as well studied as whole-breast radiation therapy, there is not full agreement about who is most likely to benefit.

Types of breast cancer that may be treated with partial breast radiation include:

• Ductal carcinoma in situ (DCIS)
• Invasive breast cancer

Other factors that may lead to the use of brachytherapy include:

• Tumor size less than 2 cm to 3 cm (about an inch)
• No evidence of tumor along the margins of tumor specimen removed
• Lymph nodes are negative for tumor, or only one node has microscopic amounts

Tell your provider what medicines you are taking.

Wear loose-fitting clothes to the treatments.

Radiation therapy can also damage or kill healthy cells. The death of healthy cells can lead to side effects. These side effects depend on the dose of radiation, and how often you have the therapy.

• You may have warmth or sensitivity around the surgical site.
• You could develop redness, tenderness, or even an infection.
• A fluid pocket (seroma) could develop in the surgical area and may need to be drained.
• Your skin over the treated area may turn red or dark in color, peel, or itch.
• You could develop a breast infection (called cellulitis).

Long-term side effects may include:

• Decreased breast size
• Increased firmness of breast or some asymmetry
• Residual seroma (area of thickening)
• Skin redness and discoloration

Studies have shown that if patients are carefully selected, overall results are the same whether patients have partial breast or whole breast radiation therapy.

Breast cancer - partial radiation therapy; Carcinoma of the breast - partial radiation therapy; Brachytherapy - breast; Adjuvant partial breast radiation - brachytherapy; APBI - brachytherapy; Accelerated partial breast irradiation - brachytherapy; Partial breast radiation therapy - brachytherapy; Permanent breast seed implant; PBSI; Low-dose radiotherapy - breast; High-dose radiotherapy - breast; Electronic balloon brachytherapy; EBB; Intracavitary brachytherapy; IBB; Interstitial brachytherapy; IMB

National Cancer Institute website. Breast cancer treatment (PDQ) - health professional version. www.cancer.gov/types/breast/hp/breast-treatment-pdq. Updated February 9, 2023. Accessed February 28, 2023.

National Cancer Institute website. Radiation therapy and you: support for people who have cancer. www.cancer.gov/publications/patient-education/radiation-and-you-2021-508.pdf. Updated April, 2021. Accessed November 18, 2022.

Otter SJ, Holloway CL, O'Farrell DA, Devlin PM, Stewart AJ. Brachytherapy. In: Tepper JE, Foote RL, Michalski JM, eds. Gunderson and Tepper's Clinical Radiation Oncology. 5th ed. Philadelphia, PA: Elsevier; 2021:chap 20.

Shah C, Harris EE, Holmes D, Vicini FA. Partial breast irradiation: accelerated and intraoperative. In: Bland KI, Copeland EM, Klimberg VS, Gradishar WJ, eds. The Breast: Comprehensive Management of Benign and Malignant Diseases. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 51.

Updated by: David Herold, MD, Radiation Oncologist in Jupiter, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 02/28/2023.