Radiation therapy is a very effective way to kill any cancer cells that remain after surgery and can reduce the risk of local recurrence (in the breast, on the chest wall or in the lymph nodes that drain the breast) by about 70%.
Radiation therapy is typically used in early stage breast cancer to treat the breast after a lumpectomy and also to treat the chest wall and lymph nodes that drain the breast in locally advanced breast cancers treated with mastectomy. It can also be used to treat tumors in the breast that cannot be surgically removed and to shrink metastatic tumors that may interfere with organ function.
Radiation therapy is treatment with high-energy rays or other particles that kill cancer cells. These radioactive beams damage the cancer cell’s DNA and thus, disrupt their ability to divide and multiply. Numerous clinical trials have demonstrated in appropriate patients, radiation therapy improves overall survival.
There are two ways to deliver radiation therapy: external beam radiation (teletherapy) and internal radiation therapy (brachytherapy).
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External beam radiation is the most commonly used type of radiation therapy for breast cancer. External beam radiation uses high-energy waves of radiation produced by a machine called a linear accelerator to target areas where tumor cells may remain even after other treatments. External beam radiation comes from across the room like a chest X-Ray. You cannot feel it and you are not radioactive when you leave.
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In internal radiation therapy, catheters are used to direct radioactive seeds into the body where they are needed to target cancer cells. Brachytherapy is commonly used for accelerated partial breast irradiation (APBI), which is a method of treating the tumor bed and margin after surgery.
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IORT entails a single dose of radiation therapy that is administered immediately after a lumpectomy. IORT delivers a single higher dose of radiation directly to the area where the tumor was removed. IORT is currently available to the majority of women who undergo lumpectomy to remove breast tumors less than two centimeters in size.
Before undergoing radiation therapy, you will meet with your radiation oncologist, who will determine the appropriate course of therapy, dosage, and delivery mechanism.
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Before external beam radiation, you will go through a simulation process in which your radiation oncologist will use a CT scan to determine the exact treatment location. After finding the exact location, the radiation therapist will mark your skin with a special ink or small permanent tattoos in this location. Your radiation oncologist will then decide on your dosage and design of the treatment fields.
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There are multiple methods of administering internal radiation therapy. Typically to determine if a brachytherapy device can technically treat what is needed, and to select the appropriate internal approach, you will have a preliminary simulation scan and your oncologist will review the size and shape of the tumor bed in the breast. If this is feasible, you will have another appointment to place the catheter (s). Once these are placed and the position confirmed you will come for treatment twice a day. During treatment, the catheter which hangs out of the breast like an IV is attached to other tubes. The radioactive seeds will pass through these tubes into the breast for the appropriate amount of time and then back out to the case where they are stored. You will not be radioactive when you leave. To avoid this invasive catheter, some centers are using a special type of external radiation called 3D conformal radiotherapy, proton beam therapy or intensity modulated radiotherapy to deliver APBI.
External beam radiation is usually administered five days a week for three to six weeks, whereas internal radiation is given twice a day for about one week. Both treatments are typically done on an outpatient basis.
Radiation therapy can cause both short-term and chronic side effects. The side effects depend on the area being treated, the type of radiation given, the total and daily dose, and the patient's overall health. Most short-term side effect go away within six months to two years after treatment. These may include:
The long-term side effects of radiation therapy can be very serious but are also extremely rare. These include:
During radiation therapy for breast cancer, women should:
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