What's the radiation therapy for the treatment of breast cancer?
Radiation therapy (or radiotherapy) uses high-energy rays to stop cancer cells from growing and dividing. Radiation therapy is often used to destroy any remaining breast cancer cells in the breast, chest wall, or axilla (underarm) area after surgery. Occasionally, radiation therapy is used before surgery to shrink the size of a tumor. A common treatment for early stage breast cancer is breast-conserving therapy. Breast-conserving therapy (BCT) is the surgical removal of a breast lump
(lumpectomy) and a surrounding margin of normal breast tissue. BCT is typically followed by at least six to seven weeks of radiation therapy. Treatment with radiation usually begins one month after surgery, allowing the breast tissue adequate time to heal. Radiation therapy may occasionally be recommended for women to destroy remaining cancer cells after mastectomy (surgical removal of the affected breast) or to shrink tumors in patients with advanced breast cancer.
Radiation is a "local treatment," meaning that it is a treatment that only affects a particular area of the breast, not the entire body. It is used to cure or control breast cancer. It can also be used before surgery to shrink the size of a tumor or after surgery to prevent the cancer cells from coming back. Radiation therapy is given in two ways: external and internal. External radiation uses a machine that directs radioactive waves or rays at the cancer and some of the normal tissue around the cancer. Internal radiation places a radioactive wire or pellet in a sealed container called an implant. The implant is placed in or near the tumor. These implants use radioactive waves to kill tumor or cancer cells. Implants can be permanent or temporary.
External beam radiation: This is the usual type of radiation therapy for women with breast cancer. The radiation is focused from a source outside the body on the area affected by the cancer. This usually includes the whole breast and, depending on the size and extent of the cancer, may include the chest wall and underarm area as well. Radiation therapy is much like getting a diagnostic x-ray, but the radiation is more intense. The procedure itself is painless.
Before your treatments start, the radiation team carefully takes measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. They will make some ink marks on your skin that they will use later as a guide to focus the radiation on the right area. Patients are usually treated 5 days a week in an outpatient center for about 6 weeks, with each treatment lasting a few minutes. A recent study from Canada found that a shorter, more intense course of treatment was effective in women with small breast tumors. Deodorants and antiperspirants can interfere with external beam radiation therapy of the underarm area, so you should avoid using them until treatments are complete.
The main side effects of external beam radiation therapy are swelling and heaviness in the breast, sunburn-like skin changes in the treated area, and fatigue. You should avoid exposing the treated skin to the sun because it can make the skin changes worse. These changes to the breast tissue and skin usually go away in 6 to 12 months.
Internal radiation: Brachytherapy (also called internal radiation) is an experimental method currently being developed to use on breast cancer patients. Instead of using radiation beams from outside the body, radioactive substances are placed directly into the breast tissue next to the cancer. Brachytherapy involves the surgical placement of 10 to 20 plastic catheters (tiny tubes called implants) into the breast tissue next to the tumor to help guide the radioactive materials to the correct area of the body. Technologists then insert pellets of radioactive substances (called Iridium-192) into the catheters. Nine or more times over the course of a week, the catheters are briefly connected to a high-dose-rate brachytherapy machine for internal radiation treatment. The treatments usually take about 10 minutes each and are painless. The tubes are usually removed after a week.
Brachytherapy is not standard practice for breast cancer patients but is currently used on cancers in other areas of the body such as the mouth, cervix, or prostate. This method is also being studied in clinical trials as the only source of radiation. So far the results have been promising, but more experience is needed with this technique before it can be recommended as standard treatment.