Breast cancer patients can be treated effectively with just one-fifth of the gruelling radiotherapy sessions many currently endure, a 10-year trial has found.
Scientists discovered that a lower total quantity of radiotherapy – delivered in fewer, but higher doses – is as safe for treating breast cancer in the long term as multiple small doses.
The promising results came at the end of a 10-year study involving more than 900 patients, led by the Institute of Cancer Research and funded by Cancer Research UK.
It was found that five larger radiotherapy doses after surgery once a week for five weeks caused similarly low rates of side effects in women with early-stage breast cancer as 25 daily doses over the same period.
The latest findings confirmed side effects remained low in the long run, after previous three-year results showed that reducing the number of doses was feasible and safe in the short term.
Tens of thousands of breast cancer patients could now be spared the ordeal of an arduous daily treatment programme and make fewer hospital visits.
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.
Judith Bliss, professor of clinical trials at the Institute of Cancer Research, said of the results, which were published in the Journal of Clinical Oncology: “After undergoing surgery to remove breast cancer, patients usually undergo weeks of radiotherapy.
“The aim of the 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.”
A total of 915 women across the UK who had early-stage breast cancer were assigned to one of three different five-week 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 to healthy breast tissue including hardening of the breast, swelling, skin reactions and changes in breast size.
Moderate or severe long-term effects were low across the three treatment groups and the most common effect was breast shrinkage.
The researchers observed no changes or minor changes in healthy breast tissue in 86% of all women in the trial at the 10-year time point.
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.
Prof Johnson said: “The NHS in England moved quickly early this year to make the switch to exactly this type of treatment, as making fewer trips to hospital is good news for people with breast cancer at any time, but especially when we were encouraging vulnerable people to stay at home more during the coronavirus pandemic.
“This important change is one of many ways that the NHS has continued to deliver cancer services despite the Covid-19 outbreak, helping tens of thousands of people safely to continue their treatment.”