Thursday, December 13, 2012
Some women diagnosed with early-stage breast cancer may be candidates for accelerated partial breast radiation treatment, in which radiation is directed to only a portion of the breast.
For this treatment, Baptist uses SAVI (Strut-Adjusted Volume Implant) technology for high dose radiation (HDR) brachytherapy that dramatically shortens the treatment time.
“Instead of treatment once a day for six-and-a-half weeks, patients can be treated twice a day for five days without a demonstrated negative effect on patients’ local recurrence rates,” says surgical oncologist Phillip Ley, MD, surgical director of the Mississippi Baptist Center for Breast Health.
Here’s how it works: With a small incision, the SAVI device is implanted into the lumpectomy cavity using local anesthesia and ultrasound guidance, and is then loaded with radioactive seeds to deliver the prescribed radiation dose via multiple channels. It provides radiation from inside the breast via HDR brachytherapy. Because it directs radiation where it’s needed and minimizes exposure to healthy tissue in the skin, lung and heart, this treatment decreases toxicity and lowers the risk of adverse cosmetic side effects.
“The original catheter had a single channel and balloon, which presented two problems,” explains Ley. “First, with no allowance for dead space around the balloon, the cavity had to be smaller than the balloon and then stretched open by the balloon. Second was skinspacing. You had to have 7 millimeters or more between the balloon and the patient’s skin. The problem is that if you get too close to the skin and radiate in 3-D, the skin could burn. Because you only had one channel, it as difficult to moderate the dose. Even if you have a big enough dose deep into the catheter, but too much of a dose on the skin, the patient will get a burn.”
At Baptist, SAVI implants are placed by the surgeon in the office as an outpatient procedure with local anesthesia. Usually beginning the next day, treatments are delivered twice a day in the radiation oncology department, with treatments scheduled six hours apart. A team of physicists, radiation therapists, and a radiation oncologist are involved with each treatment, insuring that the radiation is accurately delivered. X-rays of the SAVI device are taken daily to confirm that the position hasn’t changed so that the dose to the skin and chest wall may be minimalized.
“Patients do spend a significant amount of time in our department during the week of treatment,” says Margaret Wadsworth, MD, a radiation oncologist at Baptist and a partner with Radiation Oncology of Mississippi in Jackson. “But they complete treatment much more quickly than with traditional radiation therapy. For appropriately selected early stage breast cancers, accelerated partial breast irradiation is a convenient option with few side effects.”
After the final treatment, the implant is removed.
“The problem with the original catheter is that as a surgeon, you had to tailor the operation to fit the catheter instead of the configuration of the cavity,” says Ley. “An advantage of having the multi-channel catheter like the SAVI is that you can customize the dose, so you can put weaker sources closer to the skin. Or if your cavity isn’t perfect and there’s some dead space, the dose may be adjusted through eight channels to create a customized field.”
SAVI overcomes obstacles inherent to balloon catheters. For example, with a balloon catheter, there’s a higher chance of chronic seroma formation – a rind around the balloon, explains Dr. Ley.
“The chronic fluid collection is a problem,” he says. “If it gets hard, it can become a lump. You can drain it, but it never goes away; it just reaccumulates. You don’t have that problem as frequently with the SAVI. Especially if you have the SAVI deep in a patient’s breast, once you deploy the channels and it makes its little basket, the breast tissue interdigitates between the channels and you get an even better dosing than with balloon catheters.”
The only downside for patients: slight discomfort from the catheter, which has the potential to be cumbersome and unwieldy. Also, those five days are rarely scheduled within the same week because it’s difficult to place the catheter and also begin radiation on a Monday.
“It’s very hard not to have a weekend in between,” notes Ley. However, SAVI generally has few side effects and is much more flexible and customizable for treatment planning and dosing. “It’s a huge step forward in technology for brachytherapy.”
For more information log onto http://mbhs.org/cancer or call (601) 968-1049.
What can we help you find?close ×