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FAST is the trial that found the right five-dose schedule by measuring what the breast looked like afterwards. Giving the five treatments one a week, it showed 28.5 Gy leaves the breast no more changed than five weeks of conventional treatment, while 30 Gy leaves it visibly worse.
FAST recruited 915 women aged 50 or over with low-risk pT1 to pT2 pN0 invasive breast cancer from 18 United Kingdom centres between 2004 and 2007, and randomised them to 50 Gy in twenty-five fractions or to 30 Gy or 28.5 Gy in five once-weekly fractions of 6.0 or 5.7 Gy. Its primary endpoint was not survival or recurrence but change in photographic breast appearance at two and five years, because the question it was built to answer was how large a single fraction the normal breast will tolerate.
Five-year photographs were available for 615 of 862 eligible patients (71 percent). The odds ratio for change in photographic breast appearance against 50 Gy was 1.64 (95 percent confidence interval 1.08 to 2.49, p=0.019) for 30 Gy and 1.10 (0.70 to 1.71, p=0.686) for 28.5 Gy. For any moderate or marked physician-assessed normal-tissue effect the odds ratios were 2.12 (1.55 to 2.89, p<0.001) for 30 Gy and 1.22 (0.87 to 1.72, p=0.248) for 28.5 Gy.
The estimate that carried the field forward came out of the dose response: an alpha to beta ratio of 2.7 Gy (1.5 to 3.9) for the photographic endpoint, which implies a five-fraction schedule of 28 Gy (26 to 30) is equivalent to 50 Gy in twenty-five. That estimate is why FAST-Forward tested 26 and 27 Gy, and why 26 Gy in five fractions over one week is now the default in England.
Cancer outcomes are reported but the trial was never powered for them: at a median 9.9 years there had been eleven ipsilateral breast cancer events (three, four and four across the arms) and 96 deaths.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
915 randomised.
95 percent confidence interval 1.08 to 2.49, p=0.019 · 95 percent confidence interval 0.70 to 1.71, p=0.686
Source95 percent confidence interval 1.55 to 2.89, p<0.001 · 95 percent confidence interval 0.87 to 1.72, p=0.248
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Change in photographic breast appearance at 5 years against 50 Gy in 25 fractionsprimary | 30 Gy in 5 once-weekly fractions | - | 1.64 odds ratio | - | - | link |
| 28.5 Gy in 5 once-weekly fractions | - | 1.1 odds ratio | ||||
| Any moderate or marked physician-assessed normal-tissue effect against 50 Gy in 25 fractions | 30 Gy in 5 once-weekly fractions | - | 2.12 odds ratio | - | - | link |
| 28.5 Gy in 5 once-weekly fractions | - | 1.22 odds ratio |
Shares START-B (UK Standardisation of Breast Radiotherapy), FAST-Forward, Hypofractionation (fewer, larger radiotherapy doses), HER2-positive breast cancer.
Shares FAST-Forward, Hypofractionation (fewer, larger radiotherapy doses), Hypofractionated radiotherapy, HER2-positive breast cancer.
Shares Hypofractionation (fewer, larger radiotherapy doses), Hypofractionated radiotherapy, HER2-positive breast cancer, Breast cancer (all types).
Shares START-A (UK Standardisation of Breast Radiotherapy, trial A), START-B (UK Standardisation of Breast Radiotherapy).
Shares Hypofractionated radiotherapy, The Institute of Cancer Research, HER2-positive breast cancer, Breast cancer (all types).
Shares Hypofractionated radiotherapy, HER2-positive breast cancer, Breast cancer (all types), IMRT / IGRT (modern external beam).
Shares Hypofractionation (fewer, larger radiotherapy doses), HER2-positive breast cancer, Breast cancer (all types), IMRT / IGRT (modern external beam).
Shares Hypofractionated radiotherapy, HER2-positive breast cancer, Breast cancer (all types), IMRT / IGRT (modern external beam).