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, according to a study in the Feb. 11 issue of the New England Journal of Medicine.
Timothy J. Whelan, BM, a radiation oncologist from the Juravinski Cancer Centre and McMaster University in Hamilton, Ontario, and colleagues noted that the optimal fractionation schedule for whole-breast irradiation after breast-conserving surgery is currently “unknown.”
The researchers randomly assigned women with invasive breast cancer, who had undergone breast-conserving surgery and in whom resection margins were clear and axillary lymph nodes were negative, to receive whole-breast irradiation either at a standard dose of 50 Gy in 25 fractions over a period of 35 days (the control group) or at a dose of 42.5 Gy in 16 fractions over a period of 22 days (the hypofractionated-radiation group).
The risk of local recurrence at 10 years was 6.7 percent among the 612 women assigned to standard irradiation as compared with 6.2 percent among the 622 women assigned to the hypofractionated regimen (absolute difference, 0.5 percentage points), the authors reported.
At 10 years, Whelan and his colleagues found that 71.3 percent of women in the control group as compared with 69.8 percent of the women in the hypofractionated-radiation group had a good or excellent cosmetic outcome (absolute difference, 1.5 percentage points).
"This is win-win: shorter intense treatment is better for the patient and less costly to provide," said Whelan.
Based on their findings, the authors concluded accelerated, hypofractionated whole-breast irradiation was not inferior to standard radiation treatment in women who had undergone breast-conserving surgery for invasive breast cancer with clear surgical margins and negative axillary nodes for 10 years after treatment.
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,” he added.
The research was supported by grants from the Canadian Breast Cancer Research Alliance and the Canadian Cancer Society (through the National Cancer Institute of Canada).