In this study, women diagnosed with early-stage breast cancer who got a lower dose of radiation therapy for a shorter time after lumpectomy had the same outcome as women who got standard radiation therapy treatment (a higher dose for a longer time).
The results were presented at the 2008 American Society for Therapeutic Radiology and Oncology meeting.
Radiation therapy after breast cancer surgery is usually given as 25 treatments -- you're treated 5 times per week for 5 weeks. A Gray is the way radiation oncologists measure the dose of radiation therapy; 50 Gray is the usual amount given during the 5 weeks.
More than 1,200 women participated in this study. All of them were diagnosed with early-stage breast cancer with no lymph node involvement and all had lumpectomy. Half of the women then got standard radiation therapy (a total of 50 Gray of radiation over 5 weeks). The other half got a shorter course of radiation therapy (a total of 42.5 Gray of radiation over 3 weeks). Because the short course of radiation therapy was given over only 3 weeks, the amount of radiation given at each treatment was higher than the standard treatment. The doctors wanted to find out if this would cause more side effects. Overall, the total amount of radiation therapy given with the short course was lower than the standard course (42.5 Gray instead of 50 Gray).
The researchers followed the women for 10 years after the radiation therapy was completed and compared the women who got the short course to the women who got the standard course. The results:
Scheduling daily trips to the doctor's office for radiation therapy treatment is a problem for some women. Because it means fewer office visits, the shorter course may be easier to schedule. The shorter radiation course is common after lumpectomy for early-stage breast cancer with no lymph node involvement in Canada, but isn't as popular in the United States.
The results of this study are similar to those from other research. Still, more research is needed before shorter radiation therapy schedules are more widely used. If radiation therapy is part of your treatment plan, you might want to talk to your doctor about this study and if a shorter radiation therapy course makes sense for your unique situation. Together, you and your doctor can make the best choice for YOU.
BOSTON, Sept. 22 (MedPage Today) -- A shorter course of radiation therapy with a lower dose following lumpectomy is as effective as the longer standard adjuvant therapy for breast cancer, a researcher said here.
The rate of recurrence of breast cancer after 10 years of follow-up was 6.2% if women got 42.5 Gray of radiation over three weeks, according to Timothy Whelan, M.D., of McMaster University in Hamilton, Ontario.
In women who got the standard 50 Gray over five weeks, the rate was 6.7%, Dr. Whelan said at the American Society for Therapeutic Radiology and Oncology meeting here.
The shorter option "should be offered to select women with early-stage breast cancer," Dr. Whelan said before a plenary presentation of his data.
Dr. Whelan noted that breast irradiation after lumpectomy is "an integral component of breast conserving therapy" but the optimal fractionation for whole-breast irradiation is unknown.
To try to fill the gap, he and colleagues enrolled 1,234 women with node-negative invasive breast cancer from April 1993 through September 1996 and randomized to the shorter duration of radiation therapy or to standard treatment. Boost therapy wasn't used in order to avoid confounding factors.
Because of the higher doses of radiation at each treatment in the shorter course, he said, the concern had been that there would be a higher rate of late side effects.
But in fact, he said, there was little difference between the arms 10 years later:
In Canada, Dr. Whelan said, the shorter course has already become standard practice, because it offers a more convenient treatment schedule at about two-thirds of the cost.
The study will also likely change practice in the U.S., although changes won't come immediately, commented Anthony Zietman, M.D., of Harvard and Massachusetts General Hospital, who was not involved in the study.
Dr. Zietman said the study is a randomized trial with long follow-up "and that's the best kind of science."
He said the first change will likely be for women for whom it's "hopelessly inconvenient" to have the longer course of therapy. "For those women it will be absolutely respectable to give a shorter course of therapy and we now have data to prove that," he said.
The study was supported by the National Cancer Institute of Canada and the Canadian Breast Cancer Research Alliance. Dr. Whelan said he had no conflicts.
Primary source: International Journal of Radiation Oncology - Biology - Physics Source reference: Int J Radiat Oncol Biol Phys. 2008;72(1 Suppl)
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