MammoSite, a type of breast brachytherapy (bray-kee-therapy), uses a single catheter inserted into the breast following lumpectomy, or surgical removal of a tumor, to deliver a high dose of radiation. Once the catheter is inserted, a tiny balloon is inflated and loaded with radioactive seeds that deliver prescribed levels of radiation to targeted tissue surrounding the tumor site.
"MammoSite is a type of partial breast irradiation that delivers radiation from the inside of the breast directly to the tumor site where cancer cells are most likely to reside," said Sushil Beriwal, M.D., assistant professor at the University of Pittsburgh School of Medicine and medical director of radiation oncology at Magee-Womens Hospital of the University of Pittsburgh Medical Center (UPMC). "Ours is one of the largest single-institution studies to confirm that it does this safely and with an acceptable level of toxicity."
The study, which was designed to evaluate early outcomes of MammoSite brachytherapy, and was approved by the FDA in 2002, evaluated toxicity in 100 patients treated between June 2002 and October 2004 at the University of Pittsburgh Cancer Institute. The patients were followed between three and 30 months subsequent to treatment with an average follow-up time of one year. After treatment, patients were assessed at one week, one month and at three-month intervals. While 14 percent of women had to have the catheter removed because of various reasons, the majority of the patients (86 percent) underwent treatment.