The MammoSite Radiation Therapy System (RTS) is a device that is used to
deliver radiation therapy after a woman undergoes a lumpectomy, or surgical
removal of the cancerous tumor. This device delivers radiation from within
the space left after the cancerous tumor is removed, to the tissue directly
surrounding that cavity where tumors are most likely to recur. MammoSite
reduces the course of treatment from the traditional 6 weeks to 5 days.
How
does it work?
During a lumpectomy or shortly after, a single balloon catheter is inserted
through a small incision into the cavity created by the surgical removal of
the tumor (figure 1). The balloon tipped end is inflated with sterile saline
and contrast (for imaging) to fill the cavity. A portion of the catheter
remains outside of the breast and is dressed before the patient is sent home
(figure 2).
The patient will then return to Lourdes for her daily radiation therapy
treatments. Typical treatment duration is twice a day for five days (each
visit to the doctor will take about an hour, with 15 minutes or less for
radiation delivery). During the visit, the portion of the catheter remaining
outside of the breast is attached to a computer controlled machine, called an
afterloader. The afterloader is programmed to deliver a radioactive seed,
attached to a wire into the balloon portion of the device where it emits
radiation from within the breast (figure 3). The patient may return home
between treatments. When radiation treatment has ended, the balloon is
deflated and easily removed (figure 4).
Is the radiation exposure potentially harmful to the patient?
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).
Is the MammoSite RTS similar to brachytherapy?
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.
Is treatment with the MammoSite RTS covered by health insurance?
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.
Can any breast cancer patient be treated with the MammoSite RTS?
No. 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).
Does treatment with MammoSite RTS cause side effects?
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.
Ask your physician about MammoSite RTS for the
treatment of Breast Cancer.