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?

• After partial mastectomy (lumpectomy)
• After mastectomy (whole breast removal), if the cancer invades into the chest wall or through the skin
• After mastectomy and axillary staging if more than 4 nodes were positive.  If 1 to 3 nodes were positive after mastectomy, radiotherapy may be recommended

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?

• Whole-breast radiation therapy
• Partial-breast radiation therapy

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

1. During treatment planning, which is sometimes done the same day that you are evaluated by the radiation oncologist, the target will be determined, imaging will be used to map the area to be targeted, and dosage and schedule will be decided).

2. A virtual or clinical simulation of treatment may then be performed to ensure that the area intended for treatment is indeed the area that will be treated.

3. Treatment will last 15 to 30 minutes of each day for approximately 25-30 days of therapy.

4. Fatigue and mild breast dermatitis may be experienced, although most patients return back to baseline within a month of finishing therapy.

5. The treated area could become red, warm, or itchy. There could be mild discomfort in the area, similar to sunburn.

6. Skin may swell and darken, which may persist for a while.

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.) Only some patients qualify for this treatment, mostly those with favorable conditions—older than 50 years, smaller tumors (T1 or T2), node-negative (N0), and no need for chemotherapy.

What To Expect If Accelerated Whole Breast Radiotherapy Is Prescribed

1. During treatment planning, which is sometimes done the same day that you are evaluated by the radiation oncologist, the target will be determined, imaging will be used to map the area to be targeted, and dosage and schedule will be decided.

2. A virtual or clinical simulation of treatment may then be performed to ensure that the area intended for treatment is indeed the area that will be treated.

3. Treatment will last 15 to 30 minutes each day for approximately 16 days of therapy.

4. Fatigue and mild breast dermatitis may be experienced, although most patients return back to baseline within a month of finishing therapy.

5. The treated area could become red, warm, or itchy. There could be mild discomfort in the area, similar to sunburn.

6. Skin may swell and darken, which may persist for a while.

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

1. During treatment planning, which is sometimes done the same day that you are evaluated by the radiation oncologist, the target will be determined, imaging will be used to map the area to be targeted, and dosage and schedule will be decided.

2. A virtual or clinical simulation of treatment may then be performed to ensure that the area intended for treatment is indeed the area that will be treated.

3. Treatment will last 15 to 30 minutes of each day, twice a day for approximately 5 days of therapy.

4. Fatigue and mild breast dermatitis may be experienced, although most patients return back to baseline within a month of finishing therapy.

5. The treated area could become red, warm, or itchy. There could be mild discomfort in the area, mostly like sunburn.

6. Skin may swell and darken, which may persists for a while.

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:

• Interstitial brachytherapy—The radiation source is placed inside the area requiring therapy, mostly at the time of surgery. It can deliver high doses of radiation to the tumor, while reducing the dose to the surrounding tissue. It may be associated with increased breast induration or fibrosis post therapy, increased breast pain, or increased fat necrosis.

• 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.

• Intraoperative radiotherapy—The radiation source is placed inside the cavity at the time of surgery and a one-time dose is delivered to the area. It allows for surgery and radiation to be done at the same time. It could potentially increase accuracy of radiotherapy delivery and decrease dose of radiation to the adjacent tissue. Several different devices can be used to administer intraoperative radiation.