UK trials proton beam therapy for breast cancer patients

Tests at 22 centres will assess benefits for patients at risk of developing heart problems

A proton beam scanner at University College Hospital in London. The trial will compare the therapy – which can target radiotherapy beams more precisely – with standard radiotherapy. Getty

The UK is launching its first trial of proton beam therapy for certain patients with breast cancer.

Researchers from the University of Cambridge will assess the benefits of the therapy for patients at risk from heart problems.

The trial will compare the therapy – which can target radiotherapy beams more precisely – with standard radiotherapy for patients who are at greater risk of long-term heart problems after treatment.

It will help to determine whether proton beam therapy can help to deliver adequate doses of radiotherapy to breast tissue, while minimising off-target radiation delivered to the heart.

The Parable trial will enrol 192 people at 22 sites in the UK.

Patients will be treated with proton beam therapy at either The Christie NHS Foundation Trust in Manchester or University College London Hospitals NHS Foundation Trust.

“Although only a very small group of people are affected by a higher risk of heart problems later in life, it can still be a serious issue,” said Prof Charlotte Coles, a University of Cambridge professor and consultant oncologist at Addenbrooke’s Hospital who will lead the trial.

“Most patients treated with radiotherapy have decades of healthy life ahead of them and we need to do everything we can to avoid possible future heart problems related to treatment.

“Standard breast radiotherapy is really effective for most people with very few side effects, but there is a small group of patients for whom proton beam therapy may be a better option.”

Every year in the UK, more than 30,000 people with breast cancer receive radiotherapy following surgery as part of their treatment.

Standard breast cancer radiotherapy uses high energy X-rays to kill cancer cells. As well as lowering the risk of cancer coming back, radiotherapy can increase survival rates.

However, the risk of heart problems later in life may be higher in some people who require radiotherapy to breast tissue and lymph nodes located close to the heart.

People who are predicted to have at least a two per cent or more potential lifetime risk of heart problems from radiotherapy will be invited to take part in the trial. About 500 out of every 30,000 people who receive radiotherapy for breast cancer fall into this category.

Patients who enter the trial will either receive standard radiotherapy or proton beam therapy.

The trial will measure radiation dose delivered to the heart as an early predictor of possible heart problems, to avoid the need for lengthy follow-up checks for many years before results are available.

People in the trial will also record their experiences using questionnaires so that researchers can assess side effects including skin reactions, breast pain and swelling, and other symptoms.

“The Parable trial will measure average dose of radiotherapy delivered to the heart to predict long-term heart damage,” said Prof Judith Bliss, director of the Cancer Research UK-funded Clinical Trials and Statistics Unit at The Institute of Cancer Research, London, which is managing the trial.

“Using this early predictor will allow us to uncover the potential benefits of using proton beam therapy for long term heart health in years rather than decades.”

The trial is being led by researchers at the University of Cambridge, Institute of Cancer Research, London, and the Royal Marsden NHS Foundation Trust and managed by the Cancer Research UK-funded Clinical Trials and Statistics Unit at The Institute of Cancer Research.

It is funded by a National Institute for Health and Care Research and Medical Research Council partnership.