Radiation therapy is a mainstay of treatment for many women with breast cancer, particularly those with early-stage disease who have had a lumpectomy. It is an effective means of reducing the risk of tumor recurrence. But going to a treatment center five days a week for five to seven weeks can be exhausting and time-consuming. Moreover, breast radiotherapy may damage nearby healthy tissues, such as the heart and lungs.
At the NYU Cancer Institute, Silvia Formenti, MD, Sandra and Edward H. Meyer Professor of Radiation Oncology, Chairman of the Department of Radiation Oncology, and co-leader of the Cancer Institute's Breast Cancer Research Program, has been a leader in evaluating new ways to deliver effective doses of radiation over a shorter time period and in devising novel approaches to sparing healthy tissue. For example, she was the first to design a shorter, safer treatment regimen with an accelerated schedule of intensity-modulated radiation therapy (IMRT) delivered to the breast while a woman is lying in the prone position. During IMRT, a computer program is used to deliver highly targeted radiation beams to achieve a different dose to the whole breast compared with the tumor cavity.
The patient lies on her stomach in a special mattress made of "memory" foam, which molds to her shape. The breast to be irradiated hangs through an opening in the mattress. A "linear accelerator" delivers radiation to the affected breast. Because the breast is hanging away from the chest, this approach minimizes radiation exposure to the heart and lungs.
The results of this novel approach were recently published in the Journal of Clinical Oncology, in which Dr. Formenti and her colleagues at NYU demonstrated the feasibility of delivering IMRT with only 15 visits (daily, Monday through Friday, over three weeks) to women with early-stage breast cancer who had had a lumpectomy.
"We had an unprecedented sparing of heart and lung tissue," says Dr. Formenti. She and her colleagues are now running training sessions for visiting physicians and radiation oncology technologists.
Based on previous research in Canada which demonstrated the equivalence of higher doses of radiation delivered over a shorter period of time (three versus five weeks), the NYU Cancer Institute and other centers are continuing to determine how to optimize breast radiotherapy while sparing normal tissues as much as possible from long-term detrimental effects. "It's a form of dose-dense radiation therapy that appears as promising as dose-dense chemotherapy," says Dr. Formenti. "Patients are happier because they don't have to come in as much, and they finish their treatment sooner. But what counts the most is that with our approach, the risk of cardiovascular and lung complications of radiotherapy are drastically reduced."
Stella Lymberis, MD, who trained at NYU with Dr. Formenti, has recently joined the breast radiotherapy team. She and physicists Keith DeWyngaert, PhD, Associate Professor of Radiation Oncology, Gabor Jozsef, PhD, Associate Professor of Radiation Oncology, and Stewart Becker, PhD, Assistant Professor of Radiation Oncology, are evaluating image-guided radiation therapy as an additional technology to apply to partial breast irradiation (PBI). PBI, an investigational approach for postmenopausal women with very early, mammographically detected disease, consists of radiation delivered only to the cavity where a breast tumor has been removed.
NYU has become the first institution to assess PBI in the prone position in a new clinical trial conducted by Dr. Formenti and funded by a grant from the US Department of Defense Breast Cancer Research Program. The treatments are given five times, every other day over ten days. Since the tumor cavity may shrink or change in shape during this period, an imaging strategy called "cone beam computed tomography" will be used on the first and last days of treatment to monitor these changes. The information acquired during this new study will help radiation oncologists make necessary adjustments during the course of radiation therapy to enhance its precision, and possibly its effectiveness.
For information about clinical trials evaluating new radiation therapy approaches for breast cancer, contact Maria Fenton Kerimian at 212-731-5014.
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