LB47
A 5-fraction regimen of adjuvant radiotherapy for women with early breast cancer: first analysis of the randomised UK FAST trial (ISRCTN62488883, CRUKE/04/015)
John Yarnold1, Joanne Haviland2, Abdulla Alhasso3, Peter Barrett-Lee4, David Bloomfield5, Murray Brunt6, Charlotte Coles7, Lone Gothard1, Mark Sydenham2, Judith Bliss2, on behalf of the FAST Trialists
1Royal Marsden Hospital, Sutton, UK; 2The Institute of Cancer Research, Sutton, UK; 3Beatson Oncology Centre, Glasgow, UK; 4Velindre Hospital, Cardiff, UK; 5Royal Sussex County Hospital, Brighton, UK; 6University Hospital of North Staffordshire, Stoke-on-Trent, UK; 7Addenbrooke's Hospital, Cambridge, UK
Background
Hypofractionated breast radiotherapy (RT) using 13 or 15 fractions was
shown by the START trials to be as safe and effective as 50Gy in 2.0Gy
fractions (Fr). This trial evaluates hypofractionation further, testing 5 Fr of
5.7Gy and 6.0Gy whole breast RT against 25 Fr of 2.0Gy.
Method
Eligibility: >50 years, invasive carcinoma <3cm, breast conservation
surgery, clear margins, node negative. Patients were randomised to 50Gy
in 25 Fr (2.0Gy) or to 28.5Gy (5.7Gy) or 30Gy (6.0Gy) in 5 once-weekly
fractions. 3D dosimetry (95-107%) was mandatory. Primary endpoint was change in
photographic breast appearance at 2 and 5 years from baseline scored as none,
mild or marked. Annual clinical assessments of adverse effects were scored as
none, mild, moderate or marked. Comparisons used c2 trend test for
photographs and survival analyses of clinical assessments of adverse effects
(year 2 onwards).
Results
915 patients were recruited from October 2004-March 2007. Mean age=62.7
years; ductal histology=71%; tumour grade 1&2=88%; endocrine therapy=89%.
Median follow-up was 28.3 months. Only 17 patients (of 327 with RTOG skin
toxicity data) developed moist desquamation (12 in 50Gy, 3 in 30Gy, 2 in
28.5Gy). 686 patients had 2-year photographic assessments, with mild and marked
change in breast appearance in 18.8% and 1.7% after 50Gy, 24.1% and 9.1% after
30Gy, and 20.0% and 4.0% after 28.5Gy. Risk ratios for mild and marked change
for 30Gy vs. 50Gy were 1.39 (95%CI 0.98-1.97) and 5.55 (1.94-15.84),
p<0.001; and for 28.5Gy vs. 50Gy were 1.09 (0.75-1.58) and 2.33 (0.73-7.42),
p=0.22. Any clinically-assessed moderate/marked adverse effects in the breast
were increased for 30Gy versus 50Gy (hazard ratio, HR 2.12 (1.34-3.36),
p=0.001), but similar for 28.5Gy (HR 1.02 (0.60-1.73), p=0.94). To date, 2
local tumour relapses have been recorded.
Conclusion
28.5Gy in 5 Fr in 5 weeks of whole breast RT appears as safe in terms of
adverse effects (assessed photographically and clinically) as a standard
25-fraction schedule at this stage in follow up.
