FRIDAY, April 26, 2002 (HealthDayNews) --The device is called MammoSite, and it promises to cut the time it takes for radiation therapy following breast cancer surgery by some 85 percent.
The new treatment, expected to receive approval from the U.S. Food and Drug Administration (FDA) soon, uses an inflatable balloon to deliver radiation pellets directly to the tumor site. In addition to being faster and easier than other forms of radiation therapy, it could also do away with some of the burning and scarring associated with this kind of treatment.
"This is not for everybody, but if we select our patients very carefully -- those with small breast cancers which tend to relapse right around the surgical site -- I believe this is an excellent treatment option," says Dr. Robert Kuske, lead investigator for the multi-center trial that tested MammoSite.
Although studies on MammoSite were conducted in seven centers around the country, the number of women involved was relatively small, with a total of just 26 patients completing the trial. About half the women who started the study had to drop out, ostensibly because the balloon did not fit properly in their body.
For radiologist Dr. Beryl McCormick, MammoSite offers promise -- but she's not certain doctors know all there is to know about the treatment or its potential drawbacks.
"I think women are going to have to understand that just because the FDA approves something doesn't mean that we've all done the clinical work that we normally do outside of a study situation," says McCormick, a radiation oncologist at Memorial Sloan-Kettering Cancer Center in New York City.
"As time passes and more patients receive treatment, we are bound to learn more, both pro and con, about this system," she adds.
Radiation therapy for breast cancer is normally used following a lumpectomy -- the operation that removes only the tumor and leaves the breast intact. The radiation kills any cancer cells left in surrounding tissue.
One way to accomplish this is with external beam radiation. This involves a series of treatments that shower the breast with radiation, usually once a week for up to two months or more.
While the treatment is effective, the skin gets the largest dose of radiation because the treatment is delivered from the outside. This means radiation goes to areas that don't need it, and it can cause widespread burning -- with sometimes painful scarring.
More recently, a second technique known as brachytherapy has gained favor. This procedure delivers small radioactive pellets from the inside out. Using catheters strategically placed in the breast, the pellets are inserted directly at the site of the tumor so the strongest radiation goes directly to the tissues where the cancer was located.
Although it reduces exposure and treatment time to just five days, brachytherapy remains extremely invasive, requiring up to 24 catheters to be placed through the breast to deliver the correct amount of radiation.
MammoSite is a cousin of brachytherapy -- a procedure that also delivers site-specific radiation in just a few days. However, it does so using only one catheter.
"What makes MammoSite different is an inflatable balloon that is placed inside the breast cavity at the time of surgery -- or within a short time after surgery, in a doctor's office, under local anesthesia," Kuske says.
That balloon, Kuske says, is attached to a single catheter resembling a small drainage tube that remains outside the breast.
For the course of the treatment, the balloon is inflated to fill the cavity where the tumor was. A tiny radioactive pellet attached to a wire is inserted through the catheter into the breast cavity twice a day for five days. Here, it immediately begins delivering a precise dose of radiation to the surrounding breast tissue.
Once the therapy regimen is completed, the balloon is deflated and, along with the catheter, removed from the breast through a tiny incision. The procedure leaves a scar only about the size of a freckle or a small mole, Kuske says.
If the original tumor was deep in the breast and the breast is large, Kuske says there is virtually no skin burning associated with the treatment.
However, if the tumor was shallow and the breast is small, the pellets may be close enough to the skin to allow a small oval of flesh to experience some radiation exposure and, consequently, some burn.
"If this does occur, it's a very small area of skin just over the site of the balloon -- it does not affect the whole breast, as traditional radiation therapy can," Kuske says.
MammoSite is recommended only for tumors smaller than 2 centimeters. The shape and size of the cavity that remains after the tumor is removed must also be considered, with very large or irregularly shaped areas generally considered inappropriate for this treatment.
Additionally, McCormick says, there must be good evidence the cancer has not spread beyond the tumor and the lymph nodes are not affected.
Once approved by the FDA, MammoSite is expected to be available in major medical centers around the nation.
What To Do
For more information on MammoSite, go here.
To learn more about brachytherapy for the breast, visit the University of Wisconsin.
You can also visit the American College of Radiology for more information about radiation treatments for breast cancer
