Radiation therapy is a common treatment for breast cancer, using high-energy x-rays, protons, or other particles to kill cancer cells. It is used to treat early-stage breast cancer along with surgery for local control of the disease, and can also be used in more advanced breast cancer to control the disease or to treat symptoms, such as pain. External-beam radiation therapy is the most common form of radiation therapy for breast cancer. In this approach, a machine called a linear accelerator, or LINAC, produces radiation and delivers it as precisely directed X-ray beams.
Intensity-modulated radiation therapy (IMRT) is a special computer program used to create a personalized dose plan to deliver radiation to the breast. The doctor may place a device inside the breast at the time of surgery or soon after, that carries radiation to the tissue where the cancer originally grew (also known as the tumor bed). Radiation therapy usually starts about 3 to 4 weeks after breast-conserving therapy or mastectomy. Early studies of intracavitary brachytherapy as the only radiation after BCS had promising results in having at least the same cancer control compared to standard whole breast radiation, but they may have more complications, including poor cosmetic results.
Instead of directing radiation beams from outside the body, a device containing radioactive seeds or granules is placed in the breast tissue for a short period of time in the area where the cancer was removed (tumor bed).MSK experts recommend radiation therapy after a lumpectomy to lower the chances of cancer returning. Some women age 70 and older who have small invasive breast cancers with negative lymph nodes that are positive for the estrogen receptor (and who will receive hormonal therapy) may avoid radiation therapy after a lumpectomy. Whether or not a BCS or mastectomy has been performed, if cancer was found in the lymph nodes in the armpit (axillary lymph nodes), radiation may be given to this area. With this method, a large machine sends beams of radiation to the area of the breast that has been affected by cancer. The National Comprehensive Cancer Network (NCCN), the American Society of Clinical Oncology (ASCO) and the American Society for Radiation Oncology (ASTRO) are respected organizations that regularly review and update their guidelines.