The UK has launched its first clinical trial studying proton therapy for breast cancer patients with long-term cardiac risks.

First clinical trial evaluating proton therapy in breast cancer patients begins in the UK

January 24, 2023
by John R. Fischer, Senior Reporter
Researchers at Cambridge have launched the U.K.’s first clinical trial evaluating the efficiency of proton therapy for treating breast cancer patients, specifically focusing on those with greater risk for long-term heart complications following radiotherapy treatment.

The PARABLE Trial will compare PT with conventional radiotherapy, studying the ability to deliver proficient doses of radiotherapy to breast cancer, while reducing the spread of radiation to the heart.

It will consist of 192 patients across 22 care sites. Those chosen to receive PT instead of traditional radiotherapy will be treated at either the Christie NHS Foundation Trust in Manchester or University College London Hospitals NHS Foundation Trust. Accommodations will be provided for those far from home.

Following radiotherapy, less than 1% of patients may have a more than 1% higher chance of developing cardiac problems later in life, due to their breast tissue and lymph nodes being close to their heart or an underlying risk.

“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,” said professor Judith Bliss, director of the cancer research U.K.-funded clinical trials and statistics unit at the Institute of Cancer Research, London, in a statement.

People who would have at least a 2% or more potential lifetime cardiac risk following radiotherapy will be invited to participate, receiving either standard radiation or PT. This group makes up around 500 out of every 30,000 people who undergo radiotherapy for breast cancer annually.

In the trial, patients will fill out questionnaires about their experience, including side effects they incur such as skin reactions, breast pain and swelling, and other symptoms, with researchers hoping that PT will not increase the risk of these early side effects.

Along with age and other medical history, dose delivered to the heart will be measured to predict early small lifetime risks for heart trouble, sparing patients lengthy follow ups for many years before these problems become apparent.

“We hope that the PARABLE trial will help us to further personalize radiotherapy treatments and ensure that people can access the radiotherapy approach that is best for them, regardless of where they live,” said Dr Anna Kirby, consultant clinical oncologist at the Royal Marsden NHS Foundation Trust; breast cancer radiotherapy team lead at the Institute of Cancer Research, London, and radiotherapy lead in the PARABLE trial.