The study, which looked at Medicare records of more than 130,000 women, found that those who underwent the faster treatment, called brachytherapy, were about twice as likely to have a mastectomy in the following five years — a probable sign that the cancer had come back — as those who received conventional whole breast radiation.
“Honestly, it was somewhat shocking to me when I got this data for the first time,” Dr. Benjamin D. Smith, an assistant professor of radiation oncology at the MD Anderson Cancer Center and lead investigator on the study, which will be presented Wednesday at the San Antonio Breast Cancer Symposium in Texas.
Brachytherapy generally uses a catheter to deliver radiation directly into the cavity left after a tumor is surgically removed by a lumpectomy. Because the radiation is concentrated more where it is presumably needed, the treatment can be completed in a week, compared with six or seven weeks for whole breast radiation.
Brachytherapy has become more popular, used in 13 percent of Medicare breast cancer patients receiving lumpectomy and radiation in 2007, up from less than 1 percent in 2000, according to the MD Anderson study.
Critics have said the growth has been fueled by marketing, in the absence of much evidence that the technique is better for patients. The main suppliers of the catheters used for breast brachytherapy are Hologic, Cianna Medical and C. R. Bard.
Dr. Smith says brachytherapy costs Medicare about twice as much as the $8,000 it pays for whole breast radiation. However, some forms of whole breast irradiation are costlier than that.
Dr. Smith and his colleagues looked at the Medicare records of 130,535 people who had a diagnosis of early stage breast cancer from 2000 to 2007 and had a lumpectomy and radiation.
About 4 percent of those treated with brachytherapy underwent a mastectomy in the following five years, compared with 2.2 percent of those treated with whole breast irradiation.
Brachytherapy was also associated with a higher rate of infections, which would be expected because the catheter is inserted into the breast, as well as a higher rate of rib fractures, fat necrosis and breast pain.
One weakness is that this was not a randomized trial, so the differences in outcomes could be attributed to differences in the characteristics of the patients who chose brachytherapy and those who chose conventional irradiation. Dr. Smith said adjustments were made for known differences and the results still held. But not everyone was persuaded.
“It’s very hard to know from this particular study what the bottom line should be because of differences in patient populations,” said Dr. Abram Recht, a radiation oncologist at Harvard and Beth Israel Deaconess Medical Center. Still, he said, the higher rates of complications from brachytherapy raised a note of caution.
Dr. Rakesh Patel, chairman of the American Brachytherapy Society, said that other studies, including a randomized trial from Europe, had shown that breast brachytherapy was equivalent in effectiveness to whole breast irradiation in appropriate patients. He also said women might have gotten mastectomies for reasons other than cancer recurrence.
Dr. Patel, who is director of breast cancer services at Western Radiation Oncology, a private practice in Pleasanton, Calif., said that brachytherapy had improved a lot since the time of the study. “There’s been significant evolution and advancement in the catheters as well as our treatment planning systems,” he said.
The National Cancer Institute is sponsoring a clinical trial comparing whole breast irradiation to partial breast irradiation, including brachytherapy. But the results are not expected for several years. Many of the patients getting partial breast irradiation are not getting brachytherapy.
Article source: http://feeds.nytimes.com/click.phdo?i=ca4e847893888ce901a0a10ad14e2d88