NEW YORK — Positioning women with breast cancer facedown when they undergo radiation therapy may substantially cut the radiation dose that reaches their heart and lungs, say radiation oncologists at Memorial Sloan-Kettering Cancer Center in New York, where the technique has been used for about 10 years.
The Memorial Sloan-Kettering oncologists designed a pallet that they call the breast board to help women more comfortably lie facedown for radiotherapy. (See photo.) The board has an adjustable cutout through which the ipsilateral breast and chest wall hang down in a dependent fashion away from the thorax, while the contralateral breast is cushioned and remains on top of the board.
This setup has been used at Memorial Sloan-Kettering for breast irradiation since 1998, Dr. Beryl L. McCormick told attendees at a symposium on cardiovascular disease in cancer patients sponsored by the University of Texas M.D. Anderson Cancer Center. “We now treat as many of our breast cancer patients as possible with a prone breast board,” she said.
With a maximum follow-up of 10 years on the first patients treated this way, it's too soon to assess the impact of this approach on long-term outcomes, but the technique has attracted interest from other cancer centers, said Dr. McCormick, acting chair of radiation oncology at the cancer center in New York. The idea is to limit the radiation dose to the heart and lungs as much as possible. “The radiation dose is the same [as with standard treatment]. We just flip the patient over” from the standard supine position to prone, she said in an interview.
The danger of irradiation to the heart when breast therapy is delivered in the supine position has been documented in several studies. The heart is especially vulnerable to damage when the left breast is treated this way. For example, study results reported last year by researchers at the University of Michigan, Ann Arbor, from 795 patients with unilateral disease showed that women treated using the conventional radiation approach on their left breast were about eightfold more likely to have a later cardiac event, compared with women whose right breast was treated (Cancer 2007;109:650-7).
“Late cardiac events are real and relate to the radiation therapy technique, dose, and the volume of the heart that gets treated,” Dr. McCormick said at the meeting, also sponsored by the American College of Cardiology and the Society of Geriatric Cardiology. Adverse effects may be minimized by “avoiding treatment to as much of the heart and lung as possible.”
The “breast board” at Memorial Sloan-Kettering Cancer Center is an immobilization device for treatment of breast cancer in the prone position. Courtesy Margie Hunt, M.S.