Wake Radiology Oncology Services > Services > Brachytherapy (Implant) Programs > MammoSite<sup>®</sup> > MammoSite<sup>®</sup> Frequently Asked Questions

Q.What is the MammoSite Radiation Therapy System (RTS)?

Q.Why was MammoSite developed?

Q.How has the medical community addressed the lack of access to breast conservation therapy?

Q.Does MammoSite RTS make breast conservation therapy more accessible?

Q.How is treatment with the MammoSite RTS administered?

Q.Is the radiation exposure potentially harmful to the patient?

Q.Is accelerated partial breast irradiation as effective as whole breast radiation?

Q.Is the MammoSite RTS similar to brachytherapy?

Q.Is treatment with the MammoSite RTS covered by health insurance?

Q.Can any breast cancer patient be treated with the MammoSite RTS?

Q.Does treatment with MammoSite RTS cause side effects?

Q.Where is MammoSite currently available?

Q. What is the MammoSite Radiation Therapy System (RTS)?

A. The MammoSite^® Radiation Therapy System (RTS), an internal radiation therapy system for breast cancer, is one of the latest advances in accelerated partial breast irradiation. The device is comprised of a balloon catheter that internally administers a prescribed dose of radiation to targeted breast tissue in what is typically a five-day sequence of treatments. By internally delivering radiation directly to the tissue surrounding the original tumor, the MammoSite RTS minimizes exposure to the rest of the breast, skin, ribs, lungs and heart. The MammoSite RTS was cleared for use by the U.S. Food and Drug Administration (FDA) in May 2002, and is now available in more than 200 centers nationwide.

Q. Why was MammoSite developed?

A. More and more women who have cancerous tumors are looking for options to shorten their course of breast cancer treatment. For many women with early-stage breast cancer, breast conservation therapy—in the form of a lumpectomy and follow-up radiation treatment—is one of these options. Although breast conservation therapy allows a woman to undergo a less invasive treatment, up to 40 percent of patients with early-stage breast cancer still opt for a mastectomy, despite comparable long-term recurrence and survival rates (as reported in the New England Journal of Medicine, October 2002). Many of these patients decline breast-conserving lumpectomy because they are unable to sustain the time and travel burdens imposed by six to seven weeks of traditional external beam radiation therapy. According to a National Cancer Institute study, an increasing number of patients—about 25 percent—choose to forego any follow-up radiation treatment with the likelihood increasing the farther away a woman lives from a radiation treatment center. By eliminating the burdens associated with external beam radiation therapy, MammoSite may allow more women to enjoy the advantages of breast conservation therapy.

Q. How has the medical community addressed the lack of access to breast conservation therapy?

A. For more than a decade, the medical community has been studying partial breast irradiation as an alternative method of delivering radiation therapy to breast cancer patients. The approach most rapidly gaining in acceptance and usage across the country in accelerating the breast irradiation process is brachytherapy, which involves the internal administration of radiation via a “seed” delivered directly to the tumor site. Brachytherapy has been used for many years for the treatment of prostate cancer. Today, its benefits are being applied to address unmet needs in breast cancer.

Leading the ascension of breast brachytherapy into the clinical mainstream and enabling the concept of accelerated partial breast irradiation to become a nationwide reality for patients and physicians is MammoSite RTS. Proxima Therapeutics, Inc. has developed this brachytherapy device that internally administers a site-specific, prescribed dose of radiation to breast cancer patients in a five-day course of therapy.

Q. Does MammoSite RTS make breast conservation therapy more accessible?

A. Because of its minimally invasive nature and short duration of treatment, the MammoSite RTS could potentially eliminate the barriers to breast-conserving lumpectomy and radiotherapy. The American Brachytherapy Society states that “the ability to complete treatment in five days has the potential to provide additional women with the option of breast conservation.”

Q. How is treatment with the MammoSite RTS administered?

A. During the lumpectomy procedure or shortly thereafter, the deflated MammoSite balloon is placed inside the tumor resection cavity. A portion of the applicator shaft, a tube connected to the balloon, remains outside the breast. Once in place, the balloon is inflated with saline to fill the cavity. The balloon remains inflated for the entire time that the patient is receiving radiation therapy. After the balloon is inflated, the catheter exit site is dressed, and the patient may go home. The patient returns to the hospital or clinic for treatment on an outpatient basis where a radioactive “seed” is inserted within the inflated balloon, beginning a one-to-five day sequence of treatments. No source of radiation remains in the patient’s body between treatments or after the final procedure. When the therapy is concluded, the balloon is deflated and the MammoSite RTS catheter is easily removed.

Q. Is the radiation exposure potentially harmful to the patient?

A. Because the MammoSite RTS balloon catheter delivers radiation from within, directly to the tissue surrounding the original tumor, potential exposure to the rest of the breast, skin, ribs, lungs and heart is minimized. No source of radiation remains in the patient’s body between treatments or after the final procedure. Safety and performance of the device for delivery of internal radiation were proven clinically 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 Radiology*Biology*Physics (February 2003).

Q. Is accelerated partial breast irradiation as effective as whole breast radiation?

A. Studies, including an article to be published in the Journal of the National Cancer Institute, have found that accelerated treatment of breast cancer using conventional brachytherapy demonstrates low local recurrence rates. Based on rapidly growing clinical evidence, the American Brachytherapy Society and the American Society of Breast Surgeons have published selection criteria for patients in whom accelerated partial breast irradiation (APBI) would be considered an appropriate treatment in lieu of external beam or whole breast radiation.

Q. Is the MammoSite RTS similar to brachytherapy?

A. The MammoSite RTS is a device that delivers brachytherapy, a term applied to the process of radiating from within. Conventional breast brachytherapy has not been widely accepted by physicians and patients because of its invasiveness and complexity. Conventional brachytherapy requires the use of 15 to 30 catheters and is complex for the physician to perform. In contrast, MammoSite RTS enables treatment to be delivered with a single balloon catheter, and the procedure is relatively quick and simple to perform, with minimal discomfort to the patient.

Q. Is treatment with the MammoSite RTS covered by health insurance?

A. Radiation therapy with internal radiation is an accepted treatment for breast cancer and is covered by most insurers. Specific coverage for the MammoSite RTS will depend on a patient’s individual health care plan.

Q. Can any breast cancer patient be treated with the MammoSite RTS?

A. The MammoSite RTS is cleared to internally deliver radiation to the surgical margins following lumpectomy for breast cancer. Safety and performance of the device for internal delivery of radiation to targeted breast tissue were evaluated in a multi-center study, which involved women with early-stage breast cancer. The use of MammoSite RTS is subject to physicians’ clinical judgement in consultation with their patients. To date, physicians have generally recommended MammoSite for patients 45 years of age and older with early-stage breast cancer (e.g. a tumor size of three centimeters or less and no nodal involvement).

Q. Does treatment with MammoSite RTS cause side effects?

A. MammoSite RTS has been carefully tested in a clinical trial. Following the treatment, study participants experienced breast-related side effects, such as but not limited to redness, bruising and breast pain. All of these are common side effects of breast surgery and/or radiation therapy, and are usually only temporary. The MammoSite RTS has been used to treat thousands of patients, and a patient registry has been initiated to follow patients treated with MammoSite.

Q. Where is MammoSite currently available?

A. The MammoSite RTS is gradually being made available to physicians in different parts of the country. MammoSite is currently available in more than 200 centers nationwide. For an up-to-date list of centers already offering MammoSite RTS, please visit www.mammosite.com. Physicians and patients interested in information regarding MammoSite may call 1-86-MAMMOSITE (1-866-266-6748).