This page discusses the use of radiation therapy for the treatment of breast cancer. For a thorough review of radiation therapy for cancer treatment, please see the radiation therapy treatment monograph .

Radiation therapy is the use of penetrating beams of high-energy waves or streams of particles called radiation to treat disease. Radiation therapy destroys the ability of cancer cells to grow and divide.

Radiation of a Tumor

Radiation of Tumor
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Radiation is most often used for early stage breast cancer following breast-conserving surgery. It is also used following mastectomy if a sentinel node has been removed and shows cancer, or if 4 or more axillary nodes have been shown to have cancer. The sentinel node is the lymph node closest to the site of the original tumor. Radiation therapy may be used following mastectomy if fewer nodes are affected, depending on the other features of the case. Before deciding on whether to consider a mastectomy or lumpectomy, it is usually beneficial to consult a radiation oncologist to discuss whether radiation would be beneficial.

In the United States, if chemotherapy and radiation are both prescribed, chemotherapy usually comes first. Unlike other cancers where both therapies are given simultaneously, breast cancer patients are given radiation therapy after chemotherapy to minimize side effects.

Type of Radiation Therapy

External radiation therapy is usually used for the treatment of breast cancer. In external radiation therapy, rays are directed at the tumor from outside the body.

Some oncologists are experimenting with shorter, more powerful approaches to radiation therapy. Although these approaches are experimental, you may want to check with your doctor to determine if any of the following therapies are right for you:

  • Internal radiation therapy – internal radiation therapy, also called brachytherapy, places the radiation source as close as possible to the cancer cells. Radioactive material, sealed in a thin wire, catheter, or tube, is placed directly into the affected tissue.
  • Intraoperative therapy – intraoperative radiation combines surgery and radiation therapy. During breast-conserving surgery, after as much of the tumor as possible is removed, a large, single dose of radiation is given directly to the tumor bed and nearby areas. This therapy is sometimes given in combination with external radiation therapy.
  • Accelerated whole breast therapy – this type is similar to standard external radiation, but uses higher doses per session, which shortens the duration of the overall therapy.

What to Expect with Radiation Therapy

Radiation therapy must be planned very precisely, and is customized for each person. The therapy will be determined by the size, type, and location of your tumor.

The radiation oncologist will determine how many treatments you will receive. Each treatment generally only takes a few minutes, and the total treatment time can range from 5–8 weeks, depending on the total dose required. In most cases, women come for one session five days a week for the duration of their treatment.

During your treatment sessions, you will lie on a table built into a machine called a linear accelerator. Your entire breast and possibly some adjacent lymph nodes will be given radiation.

When you have completed all your sessions, you may be given one last additional dose of radiation at a higher dosage called a “boost.” This boost will help destroy any remaining cancer cells left in the area. The boost may be given externally, through the linear accelerator, or through internal radioactive “seeds” that are implanted into the breast.

Side Effects of Radiation Therapy

Radiation therapy may cause some temporary side effects, which may begin during treatment or may develop months or years later. Like chemotherapy, side effects from radiation result from injury to the normal tissues. Some common side effects include:

  • Fatigue
  • Sore, rough, red, or tender skin on the treated breast
  • Peeling skin on the treated breast

Discuss these and any other potential side effects with your doctor.

The risk of late complications should be discussed prior to therapy. Late complications may include injury to normal tissues such as lung and heart, and the risk of secondary malignancy caused by radiation.

For more information on radiation therapy, including how to manage the side effects, please see the radiation therapy treatment monograph.