MammoSite Radiation Therapy System

Cancer Center Acquires MammoSite Technology for Breast Cancer Treatment

Patients being treated for early-stage breast cancer by the breast surgeons and radiation oncologists at the Cancer Center at Montgomery Hospital Medical Center (MHMC) in Norristown now have access to the MammoSite Radiation Therapy System. Mammosite is a new method of delivering radiation directly to the site of the cancer (called partial breast irradiation).

For many years, women with early-stage breast cancer have chosen breast conservation therapy as an effective alternative to total mastectomy. Breast conservation involves removal of the cancer by a lumpectomy (partial mastectomy), followed by five weeks of radiation therapy to the entire breast and 1-½ weeks of radiation to the tumor bed. The combination of surgery and radiation therapy has worked extremely well in preventing local recurrence, providing good to excellent cosmetic results, and excellent survival outcomes.

MammoSite guided partial breast irradiation is a new alternative to traditional radiation therapy that offers many women a faster treatment option. Radiation therapy using the MammoSite Treatment System can be completed in five days. MammoSite works by delivering radiation inside the breast tissue at the site of the tumor removal, which is the location the tumor is most likely to recur.

MammoSite Radiation Therapy involves the use of a small, soft balloon attached to a catheter that the breast surgeon places into the lumpectomy cavity. Then, as an outpatient in the radiation oncology department, a high-dose-rate radiation source is threaded into the center of the balloon through the catheter and connecting tubes, with the help of a computer-controlled remote afterloading device.

Each radiation treatment is delivered in about five to seven minutes. The treatments are given twice daily for five days. The dose delivered in this time frame is similar radiobiologically to conventional once daily radiation over 6 ½ weeks. Because the radiation is delivered directly into the lumpectomy site from inside the breast, there is less potential to harm nearby healthy tissue and the potential risk for side effects is reduced. All treatments are given as an outpatient. At the completion of therapy, the balloon catheter is easily removed.

Clinical studies of partial breast irradiation are showing low local recurrence rates equal to traditional whole breast radiation and excellent cosmetic results. Particularly for patients with large pendulous breasts, the cosmetic results are superior to standard radiation. With mammography detecting smaller, earlier breast cancers, many women will be eligible for partial breast irradiation. Working together, the breast surgeon and radiation oncologist can determine which patients are eligible for MammoSite guided partial breast irradiation.

Breast cancer is the most common cancer among women, other than skin cancer. It is the second leading cause of cancer death in women, after lung cancer. About 211,240 women in the United States will be found to have invasive breast cancer in 2005, according to the latest statistics from the American Cancer Society.

The Cancer Center at MHMC is a member of the Jefferson Cancer Network. The Cancer Center offers comprehensive cancer care, including medical, surgical, and radiation oncology, genetic cancer risk assessment and support programs. The program has been accredited by the commission on cancer of the American College of Surgeons since 1980.

For more information about Montgomery’s new MammoSite Radiation Therapy System, please call Bruce Weiner, M.D., 610-279-3300, Estella F. Graeffe, M.D. or Lini Mehta, M.D. 610-270-2192.