Radiation therapy is an important part of breast cancer treatment for many patients. At Providence Saint John’s Health Center, breast surgeons, medical oncologists and radiation oncologists work together to determine when radiation is appropriate, which area should be treated and how radiation fits with surgery, systemic therapy and reconstruction.
Radiation services are provided through Vasek Polak Radiation Oncology, where radiation oncologists work with radiation therapists, medical physicists, dosimetrists, nurses and other specialists to plan and deliver treatment safely and precisely.
What Is Radiation Therapy for Breast Cancer?
Radiation therapy uses high-energy radiation to damage cancer cells so they can no longer continue dividing. In breast cancer care, radiation is most often used after surgery to reduce the risk that cancer will return in the treated breast, chest wall or nearby lymph nodes.
Radiation is a local treatment, meaning it is directed to a specific area rather than circulating throughout the body. The exact treatment area depends on the type of surgery, pathology findings, lymph node involvement, tumor location and other features of the cancer.
How Radiation Treatment Is Planned
Before treatment begins, patients typically undergo a planning appointment called a simulation. Imaging, usually with CT, is used to define the treatment area and identify nearby organs and tissues that should receive as little radiation as possible.
The radiation oncologist works with medical physicists and dosimetrists to calculate the treatment plan, while radiation therapists deliver the treatment and help position the patient consistently from one session to the next.
Common Radiation Therapy Methods for Breast Cancer
Radiation may be delivered to the whole breast, part of the breast, the chest wall or nearby lymph nodes depending on the diagnosis and surgical findings. Treatment recommendations are individualized rather than determined by a single technique or schedule.
External Beam Radiation Therapy
External beam radiation therapy is the most common way radiation is delivered for breast cancer. A linear accelerator directs radiation toward the treatment area from outside the body. Treatment itself is painless and is usually given as an outpatient.
External beam radiation may be used after lumpectomy to treat the whole breast or, for selected patients, only the part of the breast at greatest risk for recurrence. It may also be used after mastectomy to treat the chest wall and, when indicated, nearby lymph nodes.
Whole-Breast Radiation
Whole-breast radiation treats the remaining breast tissue after breast-conserving surgery. It is commonly used after lumpectomy because microscopic cancer cells may remain elsewhere in the breast even when the visible tumor has been removed.
Treatment schedules vary. Depending on the individual case, modern whole-breast radiation may be delivered over a shorter course than was historically used. Your radiation oncologist will recommend the schedule that best fits the clinical findings and treatment plan.
Partial-Breast Radiation
Partial-breast radiation treats only the area surrounding the site where the tumor was removed rather than the entire breast. For appropriately selected patients with favorable early-stage breast cancer or ductal carcinoma in situ (DCIS), partial-breast radiation can be an alternative to whole-breast radiation.
Partial-breast treatment may be delivered using external-beam techniques such as 3-D conformal radiation therapy or intensity-modulated radiation therapy (IMRT), or with certain forms of brachytherapy. Treatment schedules depend on the technique used and are selected according to current evidence and the individual patient’s clinical features.
Brachytherapy
Brachytherapy delivers radiation from a source positioned within or very close to the area being treated. In selected patients, breast brachytherapy can be used as a form of partial-breast radiation after lumpectomy.
The suitability of brachytherapy depends on factors such as tumor size, surgical margins, breast anatomy and other pathology findings.
Intraoperative Radiation Therapy (IORT)
Intraoperative Radiation Therapy delivers radiation directly to the area where the tumor was removed during breast-conserving surgery. It may be considered for selected patients, but it is not interchangeable with other forms of partial-breast radiation.
After the surgical oncologist removes the cancerous tumor, a radiation oncologist applies the radiation straight to the remaining tissue or tumor bed. This direct approach avoids healthy skin and organs, reducing the risk of local cancer recurrence while protecting nearby healthy tissue.This single-dose treatment is most commonly used for early-stage breast cancer, but it can also treat certain recurrent tumors in other parts of the body. Because the radiation is administered while the patient is still under anesthesia in the operating room, it can significantly shorten or eliminate the need for weeks of standard post-operative external beam radiation therapy.
Learn more about Intraoperative Radiation Therapy (IORT) for Breast Cancer.
Radiation After Lumpectomy or Mastectomy
The role of radiation depends in part on the type of breast surgery performed and the risk of cancer returning in the breast, chest wall or nearby lymph nodes.
After Lumpectomy
Most patients who undergo breast-conserving surgery receive radiation after the breast has healed. Radiation may be directed to the whole breast or, for selected patients, to only the portion of the breast around the surgical site.
The need to treat nearby lymph nodes depends on factors such as lymph node involvement, tumor location, response to systemic therapy and other clinical findings.
After Mastectomy
Radiation is not required after every mastectomy. It may be recommended when the pathology shows features associated with a higher risk of recurrence, such as certain patterns of lymph node involvement, larger tumors, close or positive margins or other higher-risk findings.
When post-mastectomy radiation is needed, treatment may include the chest wall and selected regional lymph nodes. For patients undergoing breast reconstruction, the breast surgeon and radiation oncologist coordinate treatment planning because radiation can influence reconstructive timing, tissue healing and long-term cosmetic results.
Side Effects and Monitoring During Breast Radiation
Radiation therapy is generally delivered over a series of outpatient treatments, although the number and timing of treatments vary according to the technique and treatment plan.
Common short-term effects can include skin redness or irritation, breast swelling, tenderness and fatigue. Some effects develop gradually during treatment and improve after radiation is completed. Longer-term changes can include firmness, changes in breast texture or appearance and, depending on the area treated, effects involving nearby tissues.
Your radiation oncology team monitors symptoms throughout treatment and can recommend skin care, activity guidance and other measures to help manage side effects.
How Radiation Fits With the Rest of Breast Cancer Treatment
Radiation is planned as part of the overall breast cancer treatment strategy rather than as an isolated treatment. Surgery, medical therapy, radiation and reconstruction can influence one another, and the order of treatment may vary according to the cancer and the individual patient.
For example, chemotherapy may be completed before radiation, while endocrine therapy or some targeted treatments may be given during or after the radiation course. These decisions are coordinated among the breast surgeon, medical oncologist and radiation oncologist.
Moving Forward With Radiation Treatment
The right radiation approach depends on the type of breast cancer, surgery, pathology findings, lymph node involvement and the individual patient’s treatment plan. Whole-breast, partial-breast and post-mastectomy radiation each have different roles in breast cancer care.
At the Margie Petersen Breast Center, breast surgeons, medical oncologists and radiation oncologists coordinate these decisions so patients understand why radiation is being recommended, what alternatives may be available and how it fits with the rest of their care.
Talk With Our Breast Clinic Team
The Breast Health Clinic can be reached at (310) 582-7209. If you have questions about a new breast symptom, need an evaluation or would like help determining your next step, call and a member of our team can assist you.
Learn More About Radiation Oncology at Saint John’s
Vasek Polak Radiation Oncology provides the broader scope of radiation oncology treatment at Providence Saint John’s Health Center, including treatment planning and radiation treatment delivery. They provide comprehensive, state-of-the-art radiotherapy services while care teams offer an extensive level of care and ongoing support. Radiation therapy is used to treat almost every type of cancer, including some noncancerous (benign) tumors. Treating each patient as family, the Vasek Polak Radiation Oncology team provides compassionate care throughout their treatment journey and recovery, working with other specialists to provide a multi-disciplinary approach.
Learn how radiation treatment is planned and delivered and the roles of the care team.
