The research team found that having fewer, larger doses, but a lower total dose of radiotherapy, is as safe and works as well as the standard higher dose for women with early stage breast cancer.
The trial recruited 2,236 women into one of 3 groups. There were about 750 in each group. All the women taking part had radiotherapy over 5 weeks.
- Group 1 had radiotherapy 5 times a week, with a total dose of 50 gray in 25 doses of 2 gray
- Group 2 had radiotherapy 5 times a fortnight, with a total dose of 41.6 gray in 13 doses of 3.2 gray
- Group 3 had radiotherapy 5 times a fortnight, with a total dose of 39 gray in 13 doses of 3 gray
After an average follow up of just over 5 years, the number of women whose cancer came back in the breast was low (between 3.5% and 5.2%) in all 3 groups.
The research team also looked at the effects of the different radiotherapy schedules on normal breast tissue. Nearly half the women taking part had photographs of their breast taken before radiotherapy, and again after treatment. Just under a third of these women had changes in the appearance of their breast, but most of the changes were described as mild. This did not vary much between the groups, but the women in group 3 had slightly fewer changes than women in the other groups.
Over 1,000 women completed quality of life questionnaires over a 5 year period. Changes in the appearance of the breast or breast hardness were the most common changes that they reported. This affected up to 4 out of 10 women. Women in group 3 reported fewer changes in how the breast looked than women in the other 2 groups.
Pain in the arm and shoulder affected up to a third of the women. This was reported slightly more by the women in group 1 than the women in the other 2 groups. But this difference could have been a chance result (in other words, the difference was not statistically significant 
).
In 2013, the trial team published more long term results. Having monitored the women in the trial for nearly 10 years, they found that women in group 3 still had fewer adverse changes to the breast than women in the other 2 groups. They also found that the number of women whose cancer had come back in the breast remained low at 10 years and was similar in all 3 groups.
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 ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.
