Some people receive radiation treatments for breast cancer after they’ve had surgery, or if their cancer has spread to other body parts. Radiation treatment uses high-energy rays to kill breast cancer cells. The rays are directed at the area where the tumor appeared.

Two common types of radiation treatment are external beam radiation and internal beam radiation. When radiation treatment starts depends on if you’ve had chemotherapy. It also depends on if you’ve had a mastectomy or breast-conserving surgery. Radiation can start after two weeks, to a month or later. Radiation treatment often lasts more than a month. The number of sessions depends on the type of radiation treatment you have.

External beam radiation is the most common kind of radiation treatment for breast cancer. It’s a painless treatment, like getting an X-ray. A doctor will place a machine on the outside of your body and aim the radiation beams at the area of the cancer. Your doctor will figure out where to aim the rays and how much radiation to use before each treatment. They will mark the area with temporary or permanent ink.

Each treatment only lasts a few minutes. The session setup will take longer. External radiation treatment happens five days a week for about five to seven weeks. It’s the longest type of radiation treatment available.

Short-term side effects of external radiation include:

  • fatigue
  • red, itchy, dry or tender skin
  • heavy or swollen breasts
  • red, discolored, blistered, or peeling skin

Potential long-term side effects include:

  • smaller and firmer breasts
  • breastfeeding problems
  • nerve damage
  • swelling and pain in the arm or chest
  • weakened and fractured ribs (rare)
  • future cancer in the inner lining of your blood vessels (rare)

External radiation does not leave radiation in your body. You will not be radioactive during or after treatment.

Internal breast cancer radiation is also known as brachytherapy. You doctor will place a device that contains radioactive seeds in the area of the breast where the cancer was found. For a short time, internal radiation targets only the area where breast cancer is most likely to return. This causes fewer side effects. The treatment takes a week to complete.

If you’ve had breast-saving surgery, a doctor may treat you with both internal and external radiation to increase the boost of radiation. Doctors may only perform internal radiation as a form of accelerated partial breast radiation to speed up treatment.

Potential side effects of internal radiation include:

  • nausea
  • redness
  • breast pain
  • bruises
  • infection
  • breakdown of breast fat tissue
  • weakness and fracture of the ribs (rare)

There are two common types of internal radiation treatment: interstitial brachytherapy and intracavitary brachytherapy.

During interstitial brachytherapy, a doctor will insert several small tubes into your breast where the cancer was removed. The tubes deliver radioactive pellets to that area a few times each day over several days. This procedure is not commonly used today.

Intracavitary brachytherapy is the most common type of internal breast cancer radiation. Your doctor will place a tube-like device into your breast to send radiation to the location of the cancer. The end of the device expands in the breast to keep it in place, while the other end sticks out of the breast. Outpatient treatment sessions happen twice a day for five days.

Side effects of intracavitary brachytherapy may include:

  • redness
  • bruises
  • infection
  • breast pain
  • breakdown of breast fat tissue
  • weakness and fracture of the ribs (rare)

Intracavitary brachytherapy has shown good results, but there needs to be more research done to prove its benefits. Study findings published in the Journal of the American Medical Association (JAMA) reported researchers found an association between treatment with intracavitary internal radiation and new cases of mastectomy treatment. Researchers collected data from a cohort of women aged 67 years and older with breast cancer.

Intraoperative radiation (IORT) is a treatment option given after the removal of cancer cells during surgery. A doctor will direct a single, high-dose radiation beam on the part of the exposed breast tissue where the cancer appeared. Doctors will shield normal tissues close to the area from radiation exposure.

There are two ways to administer intraoperative radiation:

  • A linear accelerator, which takes two minutes.
  • A small device that brings a high dose of radiation to the cancer area. This technique takes up to 10 minutes.

Side effects of intraoperative radiation include:

  • red, dark, dry, or irritated skin
  • changes in breast appearance and density

The type of radiation treatment you get depends on the stage of breast cancer. People with early to stage 3 breast cancer will benefit most from radiation treatment. Radiation can also help ease side effects in people with advanced breast cancer.

External whole breast radiation works best:

  • for early stage to stage 3 breast cancer
  • for tumors that are an inch or smaller
  • if the cancer is in one spot
  • if you had breast-saving surgery or a mastectomy

External beam radiation can also help treat side effects of advanced breast cancer.

Internal radiation works best:

  • for early stage breast cancer
  • if the cancer is in one spot
  • if you had breast-saving surgery or a mastectomy

Sometimes, a person with advanced breast cancer will have internal radiation.

Intraoperative radiation works best:

  • during early stage breast cancer
  • when the tumor is too close to healthy tissue for external radiation to be possible

Not everyone can have intraoperative radiation or internal beam radiation. Whether you can have these procedures depends on:

  • size and location of the tumor
  • size of your breast
  • your age
  • type of cancer cells