An intense three-week course of radiation therapy is just as effective as the standard five-week regimen for women with early-stage breast cancer.
Dr. Tim Whelan, a professor of oncology of the Michael G. DeGroote School of Medicine at McMaster University, led a team of researchers to find that women who received the accelerated therapy have a low risk of the breast cancer for as long as 12 years after treatment.
The results are to be published in the Feb. 11 issue of the New England Journal of Medicine (NEJM), and have been presented to a meeting of the American Society for Therapeutic Radiology and Oncology.
The study concluded a shorter, more intense course of therapy is as safe and effective as the standard treatment for select women who have undergone breast-conserving surgery.
Women who receive a three-week treatment - called accelerated hypofractionated whole-breast irradiation -- have a low risk of side effects and recurrence of the cancer more than decade after treatment. It is just as effective as the standard five-week course of radiation following surgery to remove the malignancy.
Dr. Whelan said the study's results will change cancer treatment practice not just in Canada, but throughout North America and around the world.
"This is win-win: shorter intense treatment is better for the patient and less costly to provide," said Dr. Whelan, who is also a radiation oncologist at the Juravinski Cancer Centre at Hamilton Health Sciences.
Many women with early-stage breast cancer are able to undergo breast-conserving therapy to keep their breast after treatment. Typically, this means they first have a lumpectomy to remove the cancer followed by a course of radiation therapy to kill any remaining cancer cells.
Between April 1993 and September 1996, researchers randomly assigned 1,234 women from Ontario and Quebec to be treated with either accelerated radiation or standard radiation. The participants were followed for 12 years to determine if the accelerated whole-breast radiation was as effective as the standard treatment.
A decade after treatment, breast cancer returned in 6.2 percent of patients treated with the accelerated radiation therapy, compared to 6.7 percent for patients treated with standard therapy. Both groups of patients also had a good or excellent cosmetic outcome from the radiation treatments.
Whelan said further research is now looking at even shorter more intensive therapy.
"We're now in the midst of further study on more intense radiation over an even shorter time, and we're seeing positive results."