Each year over 240,000 women are diagnosed with breast cancer. advances in breast cancer research include advanced surgical techniques, newer chemotherapeutic drug developments and cutting edge therapies in radiation oncology. one of these exciting new technologies involves partial breast radiation with the MammoSite System.

Radiation therapy is a standard part of breast cancer therapy in all women who have had partial mastectomy (lumpectomy) and in some patients who have undergone a mastectomy. In 1990, the National Institutes of Health (NIH) recommended breast conservation therapy (lumpectomy plus radiation) instead of mastectomy as an effective local control for most women with Stage I or II breast cancer. Subsequent analyses revealed that long-term survival rates were equivalent for patients who had undergone a mastectomy, or breast conservation with lumpectomy and radiation.

Radiation for breast cancer is typically administered daily (Monday-Friday) over the course of 6-7 weeks. treatment is delivered by using sophisticated computer controlled machines known as linear accelerators.

Recent research data has demon- strated that partial breast radiation is an excellent alternative to conventional whole breast techniques in a certain subset of patients. candidates for this therapy include women older than 45 with tumors less than or equal to 3 cm in size without the presence of metastases in axillary lymph nodes. tumor pathology may include invasive ductal carcinoma (Idc) or ductal carcinoma in situ (DCIS). This “targeted” therapy involves delivering radiation to the lumpectomy site using a simple balloon catheter delivery device (MammoSite). Unlike conventional therapy, partial breast radiation treats a smaller volume of breast tissue and can be delivered in as few as 5 days.

The MammoSite balloon can be inserted at the time of lumpectomy or following the surgery. The thin catheter with a soft balloon tip is introduced into the lumpectomy cavity site through an incision. If inserted after surgery it can be done as an outpatient with local anesthesia or conscious sedation. once the MammoSite catheter is in place the balloon is inflated to fit precisely within the cavity site. Ultrasound verification is performed to demonstrate precise expansion of the balloon and patients undergo a ct scan to allow for radiation treatment planning. a team of specialists including dosimetrists, radiation therapists, physicists and radiation oncology physicians and surgeons are involved in the MammoSite balloon placement, therapy planning, and radiation dosing and treatment delivery.

The treatment is delivered in a few minutes using a small bedside robot known as a high dose rate (HDR) remote afterloader system. This system is attached to the MammoSite catheter to allow the passage of a tiny radiation source to the center of the lumpectomy cavity and balloon. By using this technique, radiation is limited to the site of the original breast tumor. This outpatient treatment is delivered twice daily separated by 6 hours to allow the entire course to be given in 5 days. Upon completion the balloon is deflated and the catheter simply removed from the breast.

Data presented at the recent 27th annual San antonio Breast cancer Symposium by the american Society of Breast Surgeons looked at patients treated with the MammoSite Radiation Therapy System. They found good-to-excellent overall cosmetic results 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. ongoing studies are underway to evaluate various subgroup analyses and long-term data.

MammoSite partial breast radiation offers an excellent treatment option for some patients with breast cancer. Those patients with early stage disease who elect breast conservation may be candidates for this short course of targeted radiation. Many women undergo mastectomies (whole breast removal) simply to avoid the six to seven weeks of radiation they need otherwise. Women who have had mastectomies often experience the psychological toll that losing their breast takes on them. The advent of partial breast radiation using the MammoSite system allows some of these patients to elect to keep their breast intact and undergo less invasive surgical techniques.