Radiation therapy for breast cancer

Radiation therapy is treatment with high-energy rays (such as x-rays) to kill cancer cells or shrink tumors. Radiation to the breast is often given after breast-conserving surgery to help lower the chance that the cancer will come back in the breast or nearby lymph nodes. Radiation is also used after mastectomy in some cases as well as to treat cancer that has spread to other areas, for example to the bones or brain. It can be given in 2 main ways.

External beam radiation

Most often, external beam radiation is used for treating breast cancer. It is much like getting a regular x-ray but for a longer time. Radiation therapy may be used to kill cancer cells remaining in the breast, chest wall, or underarm area after surgery or, less often, to shrink a tumor before surgery.

Treatment is usually given 5 days a week (Monday through Friday) in an outpatient center. It lasts about 5 to 6 weeks. Each treatment lasts a few minutes. The treatment itself is painless. Ink marks or small tattoos may be put on your skin. These will be used as a guide to focus the radiation on the right area. You might want ask your health care team if these marks will be permanent. If you also need chemotherapy, radiation is usually given after chemotherapy is finished.

Accelerated breast irradiation: Newer methods now being studied involve giving radiation over a much shorter period of time. This is called accelerated radiation. In one approach that works as well as standard radiation, larger doses of radiation are given each day, but the course of radiation is shortened to only 3 weeks. Other approaches can shorten radiation to 5 days or even just one large dose of radiation given in the operating room right after breast-conserving surgery (before the skin is closed). Many forms of accelerated radiation are thought of as experimental at this time.

Possible side effects of external beam radiation: The main side effects of radiation are swelling and heaviness in the breast, sunburn-like changes in the skin over the treated area, and feeling very tired. The breast may feel hard for a time. Weakness and fracture of the ribs can also occur. Most skin changes get better within a few months. Changes to the breast tissue most often go away in 6 to 12 months, but it can take up to 2 years.

In some women, the breast gets smaller and firmer after radiation therapy. Radiation can lead to problems with breast reconstruction. Women who have had breast radiation may have problems breastfeeding later on. Radiation to the breast can also sometimes damage some of the nerves to the arm. This is called brachial plexopathy and can lead to numbness, pain, and weakness in the shoulder, arm and hand. Radiation of axillary lymph nodes also can cause long-term arm swelling called lymphedema. You can get more information on lymphedema in the “Lymphedema after breast cancer treatment” section.

Brachytherapy

Another way to give radiation is to place radioactive seeds (pellets) into the breast tissue next to the cancer. It may be given along with external beam radiation to add an extra “boost” of radiation to the tumor in patients who have had breast conserving surgery. It is also used in some patients as the only source of radiation (instead of radiation to the whole breast). So far the results have been good, but it may not be as a good as external beam radiation long-term.

There are different types of brachytherapy. In one method (interstitial brachytherapy), several small, hollow tubes called catheters are put into the breast around the place where the cancer was removed and are left in place for several days. Radioactive pellets are put into the catheters several times each day and then removed. This method of brachytherapy has been around longer, but it is not used as much anymore.

Another approach (intracavitary brachytherapy) involves placing a device into the space left from breast-conserving surgery, and then putting a source of radiation in the device for a short time and then removing it. Treatments are given twice a day for 5 days. This type of brachytherapy can also be thought of as a form of accelerated partial breast irradiation. This treatment can have side effects, including redness, bruising, breast pain, infection, and a breakdown of an area of fat tissue inside the breast. As with whole breast radiation, weakness and fracture of the ribs can also occur.

More studies are needed to see if brachytherapy should be used instead of whole breast radiation.