A trial looking at different ways of giving radiotherapy for women with early breast cancer (FAST)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 3

This trial compared standard radiotherapy for early breast cancer with 2 new radiotherapy schedules to see which was best at reducing the side effects from radiotherapy. This trial was supported by Cancer Research UK.

If you had breast conserving surgery for early breast cancer, you may also have had radiotherapy. Tests may have shown that there were no cancer cells in the margin of healthy tissue around your cancer, but some cancer cells could still have been left behind. The aim of radiotherapy was to destroy any cancer cells left at the site of the operation.

Radiotherapy is measured in units called ‘Grays’ (Gy) Open a glossary item and given in daily doses, called fractions . At the time of this trial, the standard treatment for women having radiotherapy for breast cancer was to give a small fraction of radiotherapy every week day for 5 weeks. Small fractions of radiation had been thought to cause fewer side effects to the healthy normal tissues of the breast. But recent results of other clinical trials (involving over 7,000 women) suggest that larger fractions may be as effective at killing cancer cells although causing fewer side effects.

Researchers in this trial wanted to find out if increasing the dose of each fraction (and using fewer fractions) while decreasing the total dose, would reduce the side effects of radiotherapy. This was a randomised trial. The women taking part were put into 1 of 3 treatment groups. Neither they nor their doctor could choose which group they were in. The 3 groups were

25 fractions of 2 Gray (total dose 50 Gray) – standard treatment
5 fractions of 6 Gray (total dose 30 Gray)
5 fractions of 5.7 Gray (total dose 28.5 Gray)

Summary of results

The trial team found that the side effects of giving 5 doses of 5.7 Gray (total 28.5 Gray) was about the same as giving 25 doses of 2 Gray (total 50 Gray) but significantly milder than 5 doses of 6 Gray (total 30 Gray).

This trial recruited 915 women. Each woman was asked to have photographs taken of their breast

Before radiotherapy
2 years after radiotherapy
5 years after radiotherapy

The research team then looked for changes in the shape, size and overall appearance of the breast since radiotherapy and graded them as none, mild or marked. Of the 915 women in the trial, the researchers were able to look at the 2 year photos of 729 women.

For the 239 who had a total dose of 50 Gray

189 had no change
46 had a mild change
4 had a marked change

For the 248 who had a total dose of 30 Gray

160 had no change
65 had a mild change
23 had a marked change

For the 242 who had a total dose of 28.5 Gray

184 had no change
49 had a mild change
9 had a marked change

After an average follow up of just over 3 years, 2 women had cancer that had come back in the same breast (local recurrence).

After an average follow up of just under 10 years the team looked at:

the chagnes in the appearance of the breast
the number of women whose cancer had come back on the same side
the number of deaths

For the changes in the breast's appearance they found no siginificance difference.

The total number of women whose cancer had come back on the same side was 11. This was:

3 women who had 50Gy
4 women who had 30Gy
4 women who had 28.5Gy

The total number of deaths was 96. This was:

30 women who had 50Gy
33 women who had 30Gy
33 women who had 28.5Gy

At 3 years the research team concluded that, regarding side effects of radiotherapy to the breast, 5 doses with a total of 28.5 Gray was about the same as 25 doses with a total of 50 Gray but was significantly milder than 5 doses with a total of 30 Gray.

The team conclude that the 10 years follow results confirm what they concluded at 3 years.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.