External beam radiation therapy (EBRT) is usually administered in the radiation oncology department five days a week (Monday through Friday) for five to six weeks, though some newer methods have cut down treatment time to a few weeks or less.

If radiation is recommended, the patient will return for a planning session called a simulation where a CT scan will be obtained in the treatment position so a plan can be devised based on the patient’s anatomy.

Each treatment session is painless and generally lasts under 10 to 15 minutes.

Possible side effects include

  • Swelling and heaviness in the breast
  • Redness or irritation in the skin over the treated area
  • Tiredness
  • Hardness in the breast

Many of the skin changes associated with external beam radiation therapy improve within the first few months of therapy. Patients are examined and followed to make sure everything is improving as expected.