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Lead investigator John Yarnold (Royal Marsden Hospital, Sutton) and colleagues say there is "mounting evidence that hypofractionation is a safe and effective approach to breast cancer radiotherapy."
The international standard radiotherapy regimen for early stage breast cancer delivers 25 daily fractions of 2.0 Gy giving a total dose of 50 Gy over 5 weeks - based on the assumption that this limits normal tissue damage while providing maximum level of tumor control.
Some clinicians have argued, however, that a lower dose delivered in fewer, larger fractions - so called hypofractionation - is feasible.
To address this uncertainty, the Standardization of Breast Radiotherapy (START) trial initiated two studies to test hypofractionation regimens in women undergoing treatment for breast cancer.
In the START 'A' trial 749 women were randomly assigned to receive the international standard radiotherapy regimen, while 1487 received either 41.6 Gy in 13 fractions of 3.2 Gy (n=750) or 39 Gy in 13 fractions of 3.0 Gy given over 5 weeks (n=737).
After a median of 5 years, the rate of tumor relapse was 3.6% after 50 Gy, 3.5% after 41.6 Gy, and 5.2% after 39 Gy.
Late adverse effects and local tumor relapse rates were similar after 41·6 Gy and 50 Gy. Meanwhile, both photographic and patient self-assessments suggested lower rates of late adverse effects after 39 Gy than after 50 Gy.
In the START 'B' trial, 1105 women were similarly assigned to receive standard radiotherapy while 1110 women were treated in a shorter time period of 3 weeks, during which time they were given 40 Gy in 15 fractions of 2.67 Gy.
The rate of tumor relapse at 5 years was 2.2% in the 40 Gy group and 3.3% in the 50 Gy group. Again, cosmetic assessments suggested lower rates of late adverse effects after 40 Gy than after 50 Gy.
Despite these favorable results, the researchers caution that longer follow-up data will be needed to discount any late-occurring events.
Lancet Oncol 2008; Advance online publication
http://www.thelancet.com/journals/lanonc
© 2008 CMG
19 March 2008
Hypofractionation radiotherapy 'effective' for breast cancer
MedWire News: Breast cancer patients given a lower overall radiotherapy dose in fewer, larger fractions, show similar recurrence rates and fewer adverse side effects compared with women who receive standard regimens, results of the UK START trials suggest.Lead investigator John Yarnold (Royal Marsden Hospital, Sutton) and colleagues say there is "mounting evidence that hypofractionation is a safe and effective approach to breast cancer radiotherapy."
The international standard radiotherapy regimen for early stage breast cancer delivers 25 daily fractions of 2.0 Gy giving a total dose of 50 Gy over 5 weeks - based on the assumption that this limits normal tissue damage while providing maximum level of tumor control.
Some clinicians have argued, however, that a lower dose delivered in fewer, larger fractions - so called hypofractionation - is feasible.
To address this uncertainty, the Standardization of Breast Radiotherapy (START) trial initiated two studies to test hypofractionation regimens in women undergoing treatment for breast cancer.
In the START 'A' trial 749 women were randomly assigned to receive the international standard radiotherapy regimen, while 1487 received either 41.6 Gy in 13 fractions of 3.2 Gy (n=750) or 39 Gy in 13 fractions of 3.0 Gy given over 5 weeks (n=737).
After a median of 5 years, the rate of tumor relapse was 3.6% after 50 Gy, 3.5% after 41.6 Gy, and 5.2% after 39 Gy.
Late adverse effects and local tumor relapse rates were similar after 41·6 Gy and 50 Gy. Meanwhile, both photographic and patient self-assessments suggested lower rates of late adverse effects after 39 Gy than after 50 Gy.
In the START 'B' trial, 1105 women were similarly assigned to receive standard radiotherapy while 1110 women were treated in a shorter time period of 3 weeks, during which time they were given 40 Gy in 15 fractions of 2.67 Gy.
The rate of tumor relapse at 5 years was 2.2% in the 40 Gy group and 3.3% in the 50 Gy group. Again, cosmetic assessments suggested lower rates of late adverse effects after 40 Gy than after 50 Gy.
Despite these favorable results, the researchers caution that longer follow-up data will be needed to discount any late-occurring events.
Lancet Oncol 2008; Advance online publication
http://www.thelancet.com/journals/lanonc
© 2008 CMG
Page last updated 2008-03-19
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