Higher doses of radiation just as safe in cancer fight
● 5 large doses per week for 5 weeks has same effect as smaller amounts more often
A lower total quantity of radiotherapy delivered in fewer higher doses is as safe in the long term for treating breast cancer as multiple small doses, the final results of a tenyear study has found.
The results of the FAST trial, led by The Institute of Cancer Research and funded by Cancer Research UK, were published in the Journal of Clinical Oncology on Tuesday.
The findings show that five larger radiotherapy doses after surgery once a week for five weeks instead of 25 daily doses over the same period cause similarly low rates of side-effects in women with early-stage breast cancer in the long run.
Researchers said that fewer treatment sessions particularly benefited patients at low risk of relapse who cannot tolerate daily radiation over long periods of time because of frailty or other chronic conditions.
The FAST trial was launched in 2004 and compared radiotherapy treatment schedules consisting of fewer but larger doses overall while decreasing the total quantity of radiation to see which was best at reducing side effects.
The three-year results of the FAST trial, published in 2011, showed that reducing the number of radiotherapy fractions to five was feasible and safe in the short term.
Researchers said that the ten-year results from the trial now confirmed that a treatment strategy involving fewer doses and fewer visits to hospital is as safe in the long term.
Judith Bliss, Professor of clinical trials at The Institute of Cancer Research, said the new study confirmed initial results that it is safe to deliver radiotherapy in fewer doses.
She added: “After undergoing surgery to remove breast cancer,patientsusuallyundergo weeks of radiotherapy.
“The aim of the FAST trial was to figure out if using fewer (radiotherapy) fractions overall, with careful consideration of the total dose, would reduce the side effects observed.
“Our initial results showed that when the total dose is adjusted appropriately it is safe to deliver radiotherapy in fewer doses and now we can confirm that this is still the case 10 years down the line.
“It is great to see that after so many years, side effects from fewer but larger doses of radiation are still low.”
NHS national clinical director for cancer Professor Peter Johnson said that the health service had made the switch to fewer treatment sessions earlier this year as the coronavirus outbreak began.
A total of 915 women across the UK who had early-stage breast cancer were assigned to one of three different fiveweek radiotherapy courses following breast cancer surgery - one course of daily doses and two delivering five larger doses weekly.
The women were then assessed annually for up to 10 years by researchers for side effects including hardening of the breast, swelling, skin reactions and changes in size.