A new device that looks quite a bit like an ordinary kitchen whisk is being used to give the option of partial breast radiation therapy to women who would otherwise not be eligible for the treatment.

The Savi brachytherapy applicator from Cianna Medical (Aliso Viejo, California), is designed to provide customized radiation therapy while minimizing exposure to healthy tissue around the breast after a lumpectomy for early stage cancer. A study of about 100 patients who have received partial breast irradiation with the whisk-like, expandable device inserted inside the breast has shown that after one year, the Savi is effective at sparing nearby healthy tissue from the effects of radiation.

The findings, reported recently at the American Society of Clinical Oncology's 2008 Breast Cancer Symposium in Washington, showed that nearly half of the women, because of their anatomy or the location of the tumor, would not have qualified for other similar internal radiation therapy techniques and would have likely needed a much longer course of therapy.

"It just allows a lot more women to get partial breast radiation," Catheryn Yashar, MD, told Medical Device Daily. Yashar is an assistant professor of radiation oncology and chief of breast and gynecological radiation services at the Moores Cancer Center at the University of California, San Diego, who led the work.

Until recently, traditional radiation treatment for women who had received a lumpectomy to remove cancer was whole breast radiation therapy, which typically has taken about six weeks, Yashar said. But the idea of partial breast radiation therapy via a process known as brachytherapy, or internal radiation, has started to catch on as doctors aim to minimize the effects of radiation on healthy tissue such as the heart, lungs, ribs and skin. In its infancy, Yashar said, the only way to deliver such treatment involved putting fifteen to twenty needles into the breast – a treatment that she says did not really catch on in the U.S.

Then another internal radiation device, the MammoSite from Hologic (Bedford, Massachusetts) became a popular option for delivering brachytherapy after a lumpectomy. The MammoSite was FDA-cleared in May 2002.

"The problem with the MammoSite and the reason new devices have come out, like the Savi, is you can't really control or modulate, or shape, the radiation," Yashar said. Physicians were also told not to place the balloon-like device any closer than 7 mm to the skin, because "if it's too close to the skin you can burn the skin or get little spider veins on the breast ... that really excluded people with A cup or B cup breasts."

The Savi device was created to overcome those downsides, Yashar said. "It enables specialists to shape the radiation to the shape and size of the woman's tumor and still miss healthy tissue."

Despite its limitations, the MammoSite device has been around longer and therefore more data is available on it. Earlier this year Hologic reported a study evaluating the MammoSite one, two and three years after treatment. The authors noted that the system was "logistically simpler, technically more reproducible, and patient 'friendly' than other interstitial brachytherapy devices (Medical Device Daily, Feb. 27, 2008).

The MammoSite device is a balloon catheter that is inserted into the cavity created by a lumpectomy and it delivers radiation from inside the lumpectomy cavity over a course of five days. Like the Savi, the MammoSite targets radiation to the area where tumors are most likely to recur, while reducing exposure to healthy tissue.

The Savi has eight to 10 "spokes", each of which can be loaded or not loaded with radiation, depending on the goal of the treatment, Yashar said. Using the device, patients with A cup or B cup breasts, or whose tumor bed is close to breast surface, may now be eligible for partial breast radiation. Like the MammoSite, the Savi is also a five-day treatment, which certainly beats the six weeks it usually takes for whole breast radiation therapy.

According to the researchers, the FDA-cleared Savi is easy to use and allowed them to change the dosages according to the woman's needs. They also noted that they saw very little radiation burning of the skin and a low infection rate.

"These findings emphasize the fact that we could expand the patient population eligible for partial breast irradiation because of the Savi," Yashar said.

She says that ultimately she sees three benefits to using the Savi device: one, it can control cancer as well as whole breast radiation; two, the treatment time is shortened from six weeks to just five days; and three, because there is less normal tissue receiving radiation compared to whole breast treatments, the cosmetic outcome is likely to be better.

21st Century Oncology (Fort Myers, Florida) also presented a scientific poster on the Savi device last week at the American Society for Therapeutic Radiology and Oncology (Fairfax, Virginia) in Boston.

Reporting on 12 recent cases in which the Savi was used, the researchers said the device "delivered excellent cosmetic results with minimal side effects, for women who had not qualified for breast conservation therapy using a previously available balloon device."

The 21st Century Oncology study found no incidence of potential side effects such as fluid collection, pigmentation change, scar tissue, or infection, the researchers said. Constantine Mantz, MD, of 21st Century Oncology, led that research team.

"Our study demonstrated that Savi provides a well-tolerated therapy for patients who otherwise would not be able to safely undergo treatment with the previously available balloon device," Mantz said. "Savi offers the physician multiple catheters for radioactive source loading and therefore total control over radiation dose distribution."

Mantz said he can "lightly load catheters near the skin or lung to limit exposure of these sensitive structures. Also, I can heavily load catheters deep within breast tissue, to increase the radiation dose to places where the patient is at risk for harboring microscopic disease."