The shorter course involves a lower total dose given in larger fractions. According to the report in The New England Journal of Medicine for February 11, the two approaches are associated with similar disease recurrence rates, toxic effects, and cosmetic outcomes at 10 years.
“Despite positive early results there was reluctance to adopt (the 3-week hypofractionated radiation) approach because of concerns regarding long-term toxicity,” lead author Dr. Timothy J. Whelan, from Juravinski Cancer Centre, Hamilton, Ontario, Canada, told Reuters Health by email. This study shows that toxicity is not increased and the shorter treatment continues to be effective, he added.
“This is a win-win situation for women with breast cancer and the health care system,” Dr. Whelan said. “Women can have a shorter more convenient treatment and it is less costly to them, and health care providers.”
He continued, “It has been suggested that some women may avoid breast-conserving surgery because of the need for lengthy radiation treatments. This may increase the attractiveness of this option by making it easier and less costly.”
Between 1993 and 1996, the 1234 women who participated in the study were randomized to receive either standard therapy (50.0 Gy in 25 fractions over 35 days) or hypofractionated therapy (42.5 Gy in 16 fractions over 22 days).
At 10 years, the risk of local recurrence was 6.2% with the hypofractionated regimen compared with 6.7% with the standard regimen. Ten-year survival rates were 84.6% with the hypofractionated regimen and 84.4% with the standard regimen.
There was no significant difference between the groups in late toxic effects on skin or subcutaneous tissue. Likewise, the percentage of subjects with a good or excellent cosmetic outcome at 10 years, based on nurse ratings, was comparable in each group: 69.8% with the hypofractionated regimen vs. 71.3% with the standard protocol.
(Just last week in The Lancet Oncology, UK researchers reported on similar patients who participated in the randomized START trials. At 5 years after treatment, there were lower rates of moderate or marked change in skin appearance, breast shrinkage and hardness, and other breast symptoms with hypofractionated radiotherapy vs the standard course. See Reuters Health story posted October 8, 2009.)
“Based on these positive results we are now exploring an even shorter treatment given over just one week,” Dr. Whelan said. “Over 1500 Canadian women are enrolled in the RAPID trial and it will continue to enroll a total of just over 2100 women. In this study radiation is limited to just the part of the breast involved with cancer. This is likely to further reduce the inconvenience of treatment and may decrease toxicity associated with radiation to improve the quality of life of women with breast cancer.”
N Engl J Med 2010;362:513-520.