Radiation therapy, or radiotherapy, is used to treat breast cancer by killing cancer cells in an area that has been specifically targeted. (Adjacent normal cells are better able to repair the damage caused by radiation than are cancer cells.)
When Is Radiation Therapy Used?
Radiation is primarily used in the following settings:
Why Is Radiation Therapy Used?
Multiple studies have shown that women who received radiation had a significant reduction of local or distant recurrence when compared to those who did not undergo radiation. They also found a significant reduction in the risk of death by breast cancer in those treated with radiotherapy. Thus, the patients who had radiotherapy when radiotherapy was indicated did better than those who did not receive radiotherapy. This is why radiation is included as part of the therapy for breast cancer.
How Is Radiation Therapy Administered?
Radiotherapy can be administered in two ways:
There are lifetime limits to the amount of radiation that can be given to a specific area of the body and this limit will determine the dosage of the radiation therapy. The physician who delivers radiation therapy (the radiation oncologist) will work with the breast surgeon and patient to determine the most suitable treatment.
Whole-Breast Radiation Therapy
Whole-breast radiation therapy treats all remaining breast tissue after a partial mastectomy (or lumpectomy). This therapy is delivered in daily doses over 4 to 6 weeks, typically Monday through Friday. In each session the patient lies in a machine that delivers the radiation, which is targeted on the breast tissue.
What to Expect If Whole Breast Radiotherapy Is Prescribed
This type of therapy can be accelerated, or shortened, using accelerated whole breast radiation therapy. (In this instance, the total dose is about 42.5 Gy.)
What to Expect If Accelerated Whole Breast Radiotherapy Is Prescribed
Partial Breast Radiation Therapy
Partial breast irradiation therapy treats only the breast tissue where the breast cancer was located; therefore, a smaller amount of normal tissue will be irradiated with this type of radiation therapy. In addition, fewer days of therapy are required to reach the desired overall dosage.
Although it is attractive to have a shorter course of radiotherapy, not everyone is a candidate. Most candidates are patients with favorable tumors.
What to Expect If Partial Breast Radiotherapy Is Prescribed
What to Expect If Accelerated Partial Breast Radiotherapy Is Prescribed
While the previously described treatments are administered using an external beam to the area, the following forms of accelerated partial breast irradiation, in which treatment duration is shorter, are administered internally:
Intracavitary brachytherapy—The radiation source is placed inside the area requiring therapy and may be done at the time of surgery or after. A balloon catheter is placed into the cavity left after the partial breast resection and is filled with radioactive material. It can deliver high doses of radiation to the tumor, while reducing the dose to the tissue around. It may be associated to increased breast induration or fibrosis post therapy, increased breast pain, or increased fat necrosis.