Short-Term Radiation Put to Test for Breast Cancer
Large-scale study comparing it with traditional six-week regimen
WEDNESDAY, Oct. 4, 2006 (HealthDay News) -- Doctors have known for years that radiation treatment following a lumpectomy for breast cancer reduces the risk of disease recurrence.
But many women find the traditional regimen -- six weeks of five daily treatments that irradiate the entire breast -- difficult and inconvenient.
Doctors for years have also offered women shorter courses of radiation therapy, including three methods of partial-breast irradiation with good track records that require only five days of treatment.
Now, for the first time, a large-scale federal study is under way to compare the traditional six-week approach to the shorter regimens.
"All of these shorter therapies are available," said Dr. Frank Vicini, principal investigator for the National Cancer Institute study that has enrolled more than half of the 3,000 women with early stage breast cancer needed to complete the study. But, he added, there hasn't been a scientific trial to compare, head to head, the longer, traditional treatment program with the shorter ones.
"The trial will allow us to say partial-breast radiation is equal or not to whole breast radiation," said Vicini, chief of oncology at William Beaumont Hospital in Royal Oak, Mich.
When it comes to a woman's decision about breast cancer treatment, "convenience does play a role," Vicini said. The six-week regimen is viewed as difficult and time-consuming by some patients, he said.
The study results will be of interest to tens of thousands of American women, because 70 percent to 75 percent of the 200,000 patients diagnosed with breast cancer annually in the United States are candidates for lumpectomies, according to the U.S. Department of Health and Human Services. Radiation is typically recommended as part two of the treatment, in order to reduce recurrence risk.
One of the three types of short-term treatment being studied by Vicini's team is a balloon brachytherapy system, called MammoSite, that was approved by the U.S. Food and Drug Administration in 2002. It involves the placement of a balloon in the breast where the tumor was. A single tube then delivers radiation into the balloon and repeats the therapy daily for five days. After that, the balloon is removed.
Another regimen is interstitial brachytherapy, also called multi-catheter therapy. It's an older system that can use as many as 20 catheters, inserted into the breast to deliver radiation to the site of the tumor. The third approach is called 3-D conformal partial breast irradiation, and it involves focusing external beam radiation on the tumor site, not the whole breast.
Women must have a tumor no more than 3 centimeters in diameter and no more than three lymph nodes that are cancerous. "One of the big goals, besides seeing if we can reduce the side effects common to traditional therapy, is to see if by making it more convenient, will we improve the use of breast-conserving therapy [the lumpectomy and radiation regimen] in women who are candidates," Vicini said.
Dr. Martin Keisch, medical director of radiation oncology at Cedars Medical Center in Miami, has been performing partial-breast irradiation for a decade. He estimates he has done the treatment on 500 patients, with only two cases of cancer recurrence.
Keisch uses both the multi-catheter and the MammoSite technique and is a trainer and consultant for the company that makes MammoSite, Cytyc Corporation of Palo Alto, Calif. Still, he said there are some patients whose tumors are suitable for partial-breast irradiation but whose anatomy isn't suitable for MammoSite.
"The system has to sit in the breast cavity just so," Keisch said. And sometimes it can't be used properly, for example, in a very small-breasted woman with a tumor that's not centrally located in her breast.
Women interested in partial-breast irradiation can look to obtain it by enrolling in the National Cancer Institute trial, offered at numerous centers nationwide, or from individual physicians. Keisch estimated that about 700 centers, besides those in the NCI study, offer MammoSite, and about 20 to 30 centers nationwide offer the multi-catheter method. It's less common, he said, to find physicians offering 3-D conformal outside the clinical trial.
To learn more about the clinical trial, visit the National Cancer Institute.