Radiation Therapy for Breast Cancer

The aim of radiation therapy is to kill cancer cells that could remain and cause your cancer to occur again in your breast, chest wall (muscles and ribs), or axilla (armpit). Radiation therapy uses high-energy x-rays to kill cancer cells that remain in your breast or surrounding lymph nodes after surgery. It is almost always used if you have breast-conserving surgery because radiation decreases the risk of local cancer recurrence and improves survival.

External beam radiation therapy (EBRT) is radiation therapy usually delivered from a machine outside your body. You typically have a treatment every day for 5 to 6 weeks.

You may also have an additional, concentrated dose of radiation therapy, called a boost, given directly to a smaller area of your breast where the cancer was found.

Side effects from radiation therapy may include swelling or heaviness in your breast; changes, such as sunburn in your skin; and fatigue.

The changes to your breast and skin usually go away in 6 to 12 months. But in some women, the breast may become smaller or firmer after radiation therapy. The size of your breast and your desire for breast reconstructive surgery are important factors that you should discuss with your doctor before having radiation therapy.

Ductal Carcinoma In Situ (DCIS)

If you have DCIS and it is treated with a mastectomy, you do not need radiation therapy. But if you have a lumpectomy, radiation therapy decreases your risk of cancer recurrence in the breast.

Radiation Therapy for Stage I Breast Cancer

Women with stage I breast cancer that has not spread to any lymph nodes and who are treated with breast-conserving surgery using a lumpectomy are currently recommended to receive radiation therapy. Standard radiation therapy after a lumpectomy consists of a limited dose of radiation to the entire breast that had cancer.

This treatment leads to long-term outcomes similar to those from a mastectomy. But women under age 50 have higher rates of local recurrences after this treatment compared with older women. Researchers think that an additional boost of radiation aimed only at the area from which the cancer was removed may reduce the rates of local recurrences, especially in younger women.

• Women with stage I breast cancer that has not spread to any lymph nodes treated with a mastectomy do not typically need radiation therapy. But some women treated with a mastectomy may have an increased risk of a local cancer recurrence.
  
  In these cases, you should discuss the role of radiation therapy to prevent local cancer recurrence with your cancer doctor. Node-negative cancers that are at increased risk of local recurrence include ones where cancer is found in the edges of the tissue that is taken out during surgery.

Radiation for Stage II or Stage III Breast Cancer

Women with node-negative stage II breast cancers treated with breast-conserving surgery using a lumpectomy are currently recommended to receive radiation therapy because radiation decreases the risk of local cancer recurrence and improves survival.

Standard radiation therapy after a lumpectomy consists of a limited dose of radiation to the entire breast that had cancer. This treatment leads to long-term outcomes similar to those from mastectomy. But women under age 50 have higher rates of local recurrences after this treatment compared with older women. Researchers think that an additional boost of radiation aimed only at the area from which the cancer was removed may reduce the rates of local recurrences, especially in younger women.

Two clinical studies have looked at treatment with mastectomy followed by chemotherapy with or without radiation in premenopausal women with stage II to stage III breast cancer. In both studies, women treated with radiation after mastectomy and chemotherapy lived longer and were less likely to have a recurrence of cancer. In the United States, however, many women who undergo a mastectomy do not receive radiation therapy. Again, this is something to discuss with your doctor.

This is particularly important if you have a high risk for local recurrence. This includes women who have:

• A cancer measuring greater than 5 centimeters in size
• Cancer present in four or more lymph nodes in the armpit (axilla)
• Cancer present in the edges of the tissue taken out during surgery

You may also be a candidate for partial-breast radiotherapy, such as brachytherapy. In this procedure, radioactive needles, seeds, or catheters are placed within the breast near the cancer to irradiate that particular area.

Other options include external-beam radiation, in which sophisticated machines enable the radiation therapist to direct the radiation right at the tumor. Another option is intraoperative radiotherapy, also called MammoSite, in which a small balloon/catheter is placed within the breast near the cancer. Which option is best for you depends on the stage of your cancer and your treatment center. 

What is the best sequence of radiation in stage I to stage III breast cancer?

The sequence of treatments is still being studied. But the current data suggest that standard treatment of early-stage breast cancer outside of a clinical study should include surgery followed by chemotherapy (if appropriate) and, lastly, radiation therapy.

Antihormonal therapy can begin during or after radiation therapy. One notable exception to this sequence is women with locally advanced breast cancer. In these women, giving chemotherapy or antihormonal treatment before surgery (known as neoadjuvant therapy) may allow some women to have breast-conserving surgery.

Radiation Therapy Stage IV Breast Cancer or Recurrent Breast Cancer

Radiation therapy also plays an important role in women with stage IV (metastatic) or recurrent breast cancer. Chemotherapy and antihormonal therapy are the main treatments for women who have stage IV breast cancer at the time of diagnosis. Local control of breast cancer has less impact on a patient's outcome because the major cause of treatment failure is a recurrence of cancer in other parts of the body. Therefore, radiation therapy to the breast that has cancer has not typically been recommended for women receiving chemotherapy and antihormonal therapy for metastatic breast cancer.

Researchers have been looking at stronger chemotherapy treatments for stage IV breast cancer. Future clinical studies will need to be designed to better look at the role of radiation in women with stage IV breast cancer.

Radiation for Palliation

Palliation refers to the control of symptoms, such as pain and bleeding. Radiation therapy plays an important role in relieving symptoms from advanced breast cancer. Women who have metastatic cancer to the bone, skin, certain lymph nodes, and other areas can get complete relief if they have radiation therapy to the area of cancer recurrence. The radiation can relieve symptoms from cancer and prevent fractures of bones if it is used early.