Radiation therapy is treatment with high-energy rays or particles that destroy cancer cells.
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 may also be recommended after mastectomy in patients either with a cancer larger than 5 cm, or when cancer is found in the lymph nodes.
Radiation is also used to treat cancer that has spread to other areas, for example to the bones or brain.
Radiation therapy can be given externally (external beam radiation) or internally (brachytherapy).
External beam radiation
This is the most common type of radiation therapy for women with breast cancer. The radiation is focused from a machine outside the body on the area affected by the cancer.
The extent of radiation depends on whether mastectomy or breast-conserving surgery (BCS) was done and whether or not lymph nodes are involved.
When given after surgery, external radiation therapy is usually not started until the tissues have been able to heal, often a month or longer. If chemotherapy is to be given as well, radiation therapy is usually delayed until chemotherapy is complete.
External radiation therapy is much like getting an x-ray, but the radiation is more intense. The procedure itself is painless. Each treatment lasts only a few minutes, but the setup time—getting you into place for treatment—usually takes longer.
Breast radiation is most commonly given 5 days a week (Monday through Friday) for about 5 to 6 weeks.
Accelerated breast irradiation: The standard approach of getting external radiation for 5 days a week over many weeks can be inconvenient for many women. Some doctors are now using other schedules, such as giving slightly larger daily doses over only 3 weeks.
Giving radiation in larger doses using fewer treatments is known as hypofractionated radiation therapy. This approach was studied in a large group of women who had been treated with breast conserving surgery (BCS) and who did not have cancer spread to underarm lymph nodes.
When compared with giving the radiation over 5 weeks, giving it over only 3 weeks was just as good at keeping the cancer from coming back in the same breast over the first 10 years after treatment.
3D-conformal radiotherapy: In this technique, the radiation is given with special machines so that it is better aimed at the area where the tumor was. This allows more of the healthy breast to be spared. Treatments are given twice a day for 5 days. Because only part of the breast is treated, this is considered to be a form of accelerated partial breast irradiation.