The study reviewed here compared the standard radiation therapy schedule to a shorter, lower-dose radiation schedule and found that the risk of the cancer coming back (recurrence) after lumpectomy to remove early-stage breast cancer was the same for both schedules.
After lumpectomy, radiation therapy often is used to reduce the risk of recurrence. Radiation therapy after breast cancer surgery is most commonly 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 (2 Gray at each treatment).
Doctors have been studying new radiation therapy schedules that involve fewer treatments with higher doses of radiation given at each treatment, but less total radiation. Also, some newer schedules are shorter than 5 weeks. These new schedules are called "low dose" or "accelerated hypofractionated" radiation therapy. The new schedules are appealing to doctors and women getting radiation for several reasons:
This study wanted to know if one of these low-dose radiation therapy schedules was as effective as the standard schedule. After lumpectomy, half of the 1,224 Canadian women in the study got radiation therapy on the standard schedule over 35 days (5 weeks). The other 612 women got radiation therapy on a low-dose schedule:
The women were followed for about 12 years after completing radiation therapy. The long follow-up time gives doctors more confidence in the results.
The risk of cancer coming back during the 10 years after diagnosis was the same for both radiation therapy schedules:
Cosmetic results during the 10 years were the same for both schedules:
These results suggest that a low-dose radiation therapy schedule is a good alternative to the standard schedule. Other studies have offered similar results. Still, some doctors feel that more research is needed before they can be completely confident that low-dose schedules are as effective as the standard schedule.
If radiation therapy is part of your treatment plan, you might want to talk to your doctor about low-dose radiation therapy schedules and whether one makes sense for you based on your unique situation and specific scheduling needs.
Breast cancer patients had similar 10-year recurrence rates and cosmetic outcomes whether they were treated with accelerated, hypofractionated whole-breast irradiation or conventional radiotherapy after breast-conserving surgery, a long-term follow-up of a randomized study showed.
Patients assigned to accelerated, hypofractionated irradiation had a 10-year recurrence rate of 6.2% compared with 6.7% for patients treated with standard irradiation.
About 70% of patients in both groups had good or excellent cosmetic outcomes, according to an article in the Feb. 11 issue of the New England Journal of Medicine.
"For women with breast cancer who are similar to the patient in this trial, an abbreviated course of radiation therapy should be more convenient and less costly than standard treatment, and its availability as a treatment option may lead to an increase in the number of women who receive breast irradiation after breast-conserving surgery," Timothy Whelan, BM, BCh, of McMaster University in Hamilton, Ont., and colleagues concluded.
Whole-breast irradiation after breast-conserving surgery significantly reduces breast cancer mortality compared with surgery alone.
However, up to 30% of women who undergo breast-conserving surgery in North America do not not have breast irradiation, in part because of its inconvenience and cost, the authors wrote.
Conventional whole-breast irradiation delivers a cumulative radiation dose of 50 Gy in 25 fractions over five weeks.
Radiobiologic models have suggested that higher radiation doses (hypofractionation) administered over a shorter period of time (accelerated therapy) will lead to similar results. An accelerated, hypofractionated regimen also might be more convenient for patients and conserve resources, the authors noted.
Several clinical studies have shown low rates of local recurrence and limited radiation-induced morbidity with a cumulative dose of 40 to 44 Gy in 15 to 16 fractions over three weeks, rather than daily fractions of 2.5 to 2.7 Gy.
Whelan and colleagues performed one such study, comparing 42.5 Gy administered in 16 fractions over 22 days versus a total radiation dose of 50 Gy given in 25 fractions over 35 days.
Their five-year results showed a local recurrence rate of 3% in both groups and similar cosmetic outcomes (J Natl Cancer Inst 2002; 94: 1143-50).
In the current report, Whelan and co-investigators described results after a median follow-up of 12 years.
The study involved 1,224 women with invasive breast cancer who were enrolled at 10 Canadian centers.
The area targeted for radiotherapy did not include the axilla or supraclavicular or internal mammary nodes, and boost irradiation to the tumor bed was not used with either regimen. After completing radiation therapy, patients had follow-up visits every six months for five years, and yearly thereafter.
The primary outcome was any local recurrence of invasive cancer in the treated breast. The 0.5% absolute difference in recurrence at 10 years was not statistically significant.
Cosmetic results were rated as good or excellent in 71.3% of patients assigned to conventional radiotherapy and 69.8% in the group that received accelerated, hypofractionated whole-breast irradiation, also a nonsignificant difference.
No cases of grade 4 skin ulceration or soft-tissue necrosis occurred in either group. The incidence of late radiation toxicity increased over time, but the 10-year incidence of grade 3 radiation-associated morbidity was 4% or less.
The study was supported by the Canadian Breast Cancer Research Alliance and the Canadian Cancer Society.
The authors' disclosures are available at NEJM.org.
Primary source: New England Journal of Medicine Source reference: Whelan TJ, et al "Long-term results of hypofractionated radiation therapy for breast cancer" N Engl J Med 2010; 362: 513-20.
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