American Society of Breast Surgeons Presents First Data from Largest Study of Partial Breast Irradiation.

COLUMBIA, Md. & SAN ANTONIO -- Initial Positive Data on 793 Patients Treated with MammoSite Radiation Therapy Presented at Annual San Antonio Breast Cancer Symposium

The American Society of Breast Surgeons today announced that initial findings from its MammoSite Patient Registry will be presented today at the 27th Annual San Antonio Breast Cancer Symposium. This data from the first 793 patients treated with the MammoSite Radiation Therapy System found good-to-excellent overall cosmetic results that are comparable to those reported with whole breast radiation therapy and that the results were reproducible among the multiple institutions participating in the study. The study reported one local recurrence (0.1%) which compares favorably to whole breast radiation.

The MammoSite Patient Registry is a national data collection program designed to analyze the efficacy of accelerated partial breast irradiation with MammoSite, which was cleared by the FDA in May 2002. Since then, MammoSite has become the most widely-used form of partial breast irradiation for the treatment of breast cancer and has been used to treat more than 7,000 women in hundreds of treatment centers nationwide. Partial breast irradiation is the emerging practice of delivering radiation only to the tissue where cancer is most likely to recur, minimizing exposure to healthy tissue. The American Society of Breast Surgeons' Patient Registry is the largest study of partial breast irradiation to date.

"We're pleased that the data from the American Society of Breast Surgeons' MammoSite Patient Registry mirrors what we're seeing in clinical practice in terms of good cosmetic results and reproducibility," said Frank Vicini, M.D., radiation oncologist at William Beaumont Hospital in Royal Oak, Michigan and co-principal investigator of the MammoSite Patient Registry. "I look forward to continued evaluation of this promising technology, which has been an appealing treatment option for both patients and their doctors."

In poster session #4070 entitled, "First Analysis of Patient Demographics and Technical Reproducibility, Cosmesis and Early Toxicity by the American Society of Breast Surgeons' MammoSite Breast Brachytherapy Registry Trial in 793 Patients Treated with Accelerated Partial Breast Irradiation," data from 71 participating institutions shows MammoSite is an acceptable treatment option. The American Society of Breast Surgeons assumed responsibility for management of the MammoSite Patient Registry in November of 2003. Since then, the Society has successfully achieved its goal of enrolling 1,500 patients in the study.

"The American Society of Breast Surgeons' Patient Registry will continue to analyze additional data from the MammoSite Registry in order to provide the medical community with long-term information for this internal, five-day radiation therapy," said Peter Beitsch, M.D., director of the Dallas Breast Center and co-principal investigator of the MammoSite Patient Registry. "As MammoSite continues to be more widely adopted, data from this patient registry is assisting physicians to identify the most suitable patients who will benefit most from MammoSite, so that we can continue to progress towards less invasive, less time consuming treatments for breast cancer."

About The American Society of Breast Surgeons

Founded in 1995, the American Society of Breast Surgeons represents nearly 1,900 surgeons nationwide and is one of the fastest growing subspecialty surgical groups in the country. It was formed to encourage the study of breast surgery, promote research and development of advanced surgery techniques, improve standards of practice for breast surgery in the United States and serve as a forum for the exchange of ideas. For more information, please visit the American Society of Breast Surgeons' Web site at www.breastsurgeons.org.

About MammoSite

MammoSite is a minimally invasive balloon catheter that is inserted into the cavity created by a lumpectomy. During a five-day course of therapy, a tiny radioactive seed attached to a wire is inserted into the balloon, delivering prescribed levels of radiation under precise computer control to the targeted tissue surrounding the cavity.

No source of radiation remains in the patient's body between treatments or after the final procedure. Since its clearance by the FDA in May 2002, MammoSite has been used to treat thousands of early-stage breast cancer patients at more than 400 U.S. hospitals and treatment centers. For a list of treatment centers, refer to www.mammosite.com.

Safety and performance of MammoSite were evaluated in a multi-center study, which involved women with early-stage breast cancer. The results of the study were published in the International Journal of Radiation Oncology-Biology-Physics (February 2003).

A study published in the American Journal of Surgery found that, over the course of six years, partial breast irradiation produces comparable results to whole-breast radiation therapy in preventing breast cancer recurrence in women with early-stage breast cancer who are treated with breast-conserving therapy.