New Breast Radiation Therapy Studied

Researchers Concerned About Possibility of Side Effects

For breast cancer patients who have undergone a lumpectomy (breast-conserving surgery), the current standard of care after surgery is "whole breast" irradiation, which has a success rate of more than 95%. Newer methods of treating just the lumpectomy site are being presented as faster and more convenient, but experts caution against widespread use until safety and effectiveness can be proven.

M. D. Anderson researchers, who are studying the therapies in a new clinical trial, are concerned, says radiation oncologist Eric Strom, M.D., clinical medical director of M. D. Anderson's Nellie B. Connally Breast Center. The main reasons are that no long-term information exists about side effects or successfulness of these new techniques, known as partial breast irradiation (PBI)

"We consider PBI to be investigational, even though some of the tools have been approved by the Food and Drug Administration," Strom says. "Many practitioners are using it as a standard treatment option, but we think the data doesn't support that. The safety and efficacy of PBI has yet to be proven."

"Investigational" radiation treatments take less time

M. D. Anderson is conducting a study of all three types of PBI, two of which involve brachytherapy (the placement of tiny radioactive seeds within the tumor site).

Half of the study participants will receive traditional whole breast irradiation. The other half will receive one of the following PBI treatments:

MammoSite -This method involves inserting a balloon through a catheter (tube) into the (saline-filled) lumpectomy cavity and inflating it to fill the cavity. The balloon is in place for several days for treatment planning and one week of treatment. A radioactive seed is inserted into the center of the balloon, left in place for five to 10 minutes and then removed. The patient undergoes treatment twice a day for five consecutive days.

Interstitial brachytherapy- Similar to MammoSite, interstitial brachytherapy uses up to a dozen plastic catheters inserted into and around the lumpectomy cavity. The radioactive source is placed into each of these tubes and then removed twice daily for five days.

3D conformal radiation therapy (CRT)- With CRT, three to five external radiation beams provide targeted treatment to the lumpectomy cavity from outside the body, also on a twice daily schedule for five days.

The biggest advantage of PBI is that it takes less time - one week, compared to five or six weeks of daily treatment with whole breast irradiation and treats a smaller portion of the breast.

Strom points out, however, that convenience aside, whole breast irradiation yields results that may be hard to beat. "External beam radiation has a 95% to 98% success rate, with a very low incidence of side effects," he says. "PBI isn't likely to be better, and it might be worse."

Strom's colleague, Julia Oh, M.D., concurs. "Brachytherapy done incorrectly can be very unforgiving," says Oh, an assistant professor in the Division of Radiation Oncology. "People focus on the convenience, but they need to realize that the side effects are very different."

Temporary skin tanning is the main side effect of whole breast irradiation, but partial breast irradiation can cause temporary skin blistering or permanent skin or breast scarring in some patients. To reduce the possibility of side effects in the M. D. Anderson study, patients will be carefully selected based on anatomy, tumor location and size.

For more information, please contact the M. D. Anderson Information Line at 1-800-392-1611, option 3.