Dr Kotryna Temcinaite, Senior Research Communications Manager at Breast Cancer Now, said:
“Around 55,000 women and 370 men are diagnosed with breast cancer every year in the UK and each patient will have their own treatment plan.
"Serious side effects from radiotherapy are very rare, but for a small number of people radiotherapy could increase their risk of heart problems later in life, because of underlying health issues or the way radiotherapy needs to be targeted to best treat the cancer.
"We must find new and effective treatment options for people at risk of these complications so that everyone with breast cancer can live and is supported to live well now and in the future.
"If the PARABLE trial shows that proton beam therapy works better than standard radiotherapy for these people, it could pave the way for this treatment being made available through the NHS for those who need it.
“If patients have questions about radiotherapy, we advise them to speak to their treatment teams, or to call Breast Cancer Now’s free Helpline on 0808 800 6000 to talk to one of our expert nurses.”