Partial Breast Radiation
Accelerated, partial breast irradiation (PBI) is a new way to incorporate radiotherapy in the treatment of women with breast cancer. Partial breast irradiation shortens the treatment time from 6 1/2 weeks to 5 days.
It is a technique in which just the tumor cavity, representing the area where the tumor was removed from and approximately 1 cm of normal breast tissue around it, is treated with radiation instead of the entire breast. In appropriate candidates the risk of a local recurrence (cancer returning where it was originally present in the breast) is comparable to treatment with full breast radiation. Usually the patient will visit with both her surgeon and radiation oncologist prior to surgery to discuss her candidacy for PBI. Recent consensus guidelines from the American Society of Therapeutic Radiation Oncology help the radiation oncologists to guide patients in deciding whether PBI or treating the full breast is most appropriate.
The most common technique for PBI is using a balloon device which is placed in the breast, usually a few days after the surgery once the pathology results are available to ensure a woman is a good candidate for the procedure. Currently two balloon devices are on the market (Mammosite™ and Contura™).
Once a balloon catheter is placed in a woman’s breast, the patient sees the radiation oncologist. A simulation (planning session) is performed. This generally takes one hour. Typically, the patient then begins the 5-day course of treatment a few days later. Treatments are given twice daily with a break of 4-6 hours between treatments. There are a total of 10 treatments.
Prior to each treatment, there is verification to ensure the balloon is in the proper place (tumor cavity) in the breast and has not changed from the planning position. Then the catheter portion from the balloon that is outside of the patient’s breast is connected to a machine which has a wire containing radiation. The wire with radiation goes down the catheter and stays there for a few minutes, delivering the prescribed dose of radiation. Once completed, the radiation source goes back into the machine. The catheter is disconnected.
The patient no longer has any radiation and may leave the radiation suite with the risk of radiation exposure to her family. She returns at the next time for her next treatment. At the end of the 10 treatments, the saline (water) in the balloon is removed and the catheter is removed from the woman’s breast.