Safer, More User-Friendly Breast Radiotherapy
Radiation therapy is the mainstay treatment for many women with breast cancer, particularly those with early-stage disease who have had a lumpectomy. While effective at preventing recurrence, it also requires a potentially exhausting regimen of visits to a treatment center five days a week, for five to seven weeks. Moreover, breast radiotherapy may damage nearby healthy tissues, such as the heart and lungs.
At the NYU Cancer Institute, Silvia Formenti, MD, the Sandra and Edward H. Meyer Professor of Radiation Oncology, has long been a leader in developing new ways to spare healthy tissue and to deliver effective doses of radiation over a shorter time period. Dr. Formenti, who is also Chairman of the Department of Radiation Oncology and co-leader of the Cancer Institute’s Breast Cancer Research Program, was the first to design a shorter, safer treatment regimen for breast cancer using an accelerated schedule of intensity-modulated radiation therapy (IMRT).
During IMRT, a computer program delivers highly targeted radiation beams to send different doses to the tumor cavity and the rest of the breast. The patient lies on her stomach in a special mattress made of “memory” foam, which molds to the patient’s shape. The breast to be irradiated hangs through an opening in the mattress. A “linear accelerator” delivers radiation to the affected breast. Because the patient's breast is hanging away from her chest, this approach minimizes radiation exposure to the heart and lungs.
Details on this new approach recently appeared in the Journal of Clinical Oncology. Dr. Formenti and her colleagues demonstrated the feasibility of delivering IMRT in only 15 visits to women with early-stage breast cancer who had had a lumpectomy. Patients received therapy daily, Monday through Friday, for three weeks.
“We were happy to report that we had an unprecedented sparing of heart and lung tissue,” says Dr. Formenti. The research team is now running training sessions for visiting physicians and radiation oncology technologists who want to learn the approach.
Previous studies in Canada demonstrated that higher doses of radiation delivered over a shorter, three-week period of time are equivalent to standard doses given over five weeks. In related research, NYU Cancer Institute and others are continuing to explore how to optimize breast radiotherapy while sparing normal tissues as much as possible from long-term harm. “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, recently joined the breast radiotherapy team. She and physicists Keith DeWyngaert, PhD, Associate Professor of Radiation Oncology, Gabor Jozsszef, PhD, Assistant Associate Professor of Radiation Oncology, and Stewart Becker, PhD, Assistant Professor of Radiation Oncology, are evaluating image-guided radiation therapy (IGRT) as an additional technology to apply to partial breast irradiation (PBI). An investigational approach for postmenopausal women with very early disease detected by mammogram, PBI delivers radiation only to the cavity where a breast tumor has been removed.
In a new clinical trial conducted by Dr. Formenti and funded by the US Department of Defense Breast Cancer Research Program, NYU became the first institution to assess PBI in the prone position. The treatment was given five times, every other day over ten days. Since the tumor cavity may shrink or change shape during this period, an imaging strategy called “cone beam computed tomography” monitors any changes on the first and last days of treatment. Information from 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.
Posted: 4/3/08
