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More than 1,000 people have already joined the UK’s largest ever breast cancer radiotherapy trial, which is investigating whether treatment can be safely shortened.
The FAST-Forward Boost trial, led by The Institute of Cancer Research, London, and funded by the National Institute for Health and Care Research (NIHR), will look at whether the full course of treatment, including an additional tumour site ‘boost’ dose, can safely be delivered in just five days, cutting treatment time by up to 75 per cent.
The trial’s Chief Investigator is Professor Anna Kirby, Professor in Radiotherapy for Breast Cancer at The Institute of Cancer Research, London, and Consultant Clinical Oncologist at The Royal Marsden NHS Foundation Trust.
Almost 40 hospital sites across the UK
Since recruitment opened in April 2025, the trial has expanded to include 39 hospital and cancer centres across the UK. Many participating centres have also implemented new radiotherapy techniques as part of their involvement.
The research team are celebrating the milestone by thanking the people who have chosen to take part in the study, as well as recognising the contribution of radiotherapy, research and clinical teams at participating hospitals across the country.
Reducing the number of hospital visits
Around 37,000 people with breast cancer receive radiotherapy each year in the UK to reduce the risk of their cancer returning or spreading. Traditionally, treatment has involved 15 daily sessions, with some people receiving an additional ‘boost’ dose to the tumour site, extending treatment to 23 days.
The earlier FAST-Forward trial, involving more than 4,000 people and 10 years of follow-up, showed that a five-day schedule is as safe and effective as 15 treatments by using a higher daily dose.
Meanwhile, another study, called the IMPORT HIGH trial, tested the ‘simultaneous integrated boost’ (SIB) technique, which delivers a boost dose during, rather than after, the main radiotherapy treatment, reducing total treatment time to 15 days.
Comparing one week of treatment with three weeks
The FAST-Forward Boost trial has built on the findings of both these trials to compare one-week, five-treatment SIB radiotherapy with the current three-week, 15-treatment SIB approach to determine whether the shorter course is equally safe and effective.
Participants in the trial are assigned to receive either standard radiotherapy SIB treatment, consisting of 15 daily treatments given over three weeks, or one of two new radiotherapy SIB treatments given as five daily treatments over one week.
Assessing side effects of the shorter treatment
Researchers will assess side effects, including tiredness and skin changes, and the impact of treatment on people’s day-to-day lives. They will also look at whether people experience fewer side effects and recover more quickly, and whether a shorter treatment reduces the financial impact on both the NHS and patients.
The nationwide rollout of FAST-Forward Boost has brought together clinical, research and radiotherapy teams across the UK. For many participating hospitals, involvement in the trial has supported the introduction of integrated boost techniques, while enabling centres to share expertise and refine approaches to high-quality radiotherapy planning and delivery.
The trial aims to recruit 4,830 people by 2028. All participants will be followed up for five years, with results expected in 2033.
The Clinical Trials and Statistics Unit at the ICR
The FAST-Forward Boost, FAST-Forward and IMPORT HIGH trials were sponsored by the ICR and managed by the Clinical Trials and Statistics Unit at the ICR (ICR-CTSU).
The ICR-CTSU, which is core-funded by Cancer Research UK, strives to develop and deliver trials that offer the cancer patients of today the opportunity to access cutting-edge treatments, while gaining as much knowledge as possible to benefit the cancer patients of tomorrow.
The ICR-CTSU recruits around 1,200 patients each year into its trials from around 100 UK NHS sites and international hospital sites. Many of these trials have led to improvements in how we treat cancer in the UK and around the world.
Health and Social Care Secretary Yvette Cooper visited Professor Anna Kirby at The Royal Marsden, one of the 39 hospitals taking part in FAST-Forward Boost, to learn more about the trial.
‘Reaching 1,000 patients is a fantastic milestone’
Professor Anna Kirby, Chief Investigator of the FAST-Forward Boost trial, Professor in Radiotherapy for Breast Cancer at The Institute of Cancer Research, London, and Consultant Clinical Oncologist at The Royal Marsden NHS Foundation Trust, said:
“Reaching 1,000 participants is a fantastic milestone. It reflects the commitment of patients and clinical teams across the UK to answering an important question about how we can improve breast radiotherapy for patients.
“It is particularly heartening to see so many women, at a challenging time in their own lives, choosing to take part in research that could help improve treatment for women with breast cancer in the future. We are incredibly grateful to every one of them.
“The response has been hugely encouraging. Patients want to know that their treatment can safely and effectively be given in a shorter timeframe, and clinicians are equally keen to find evidence to improve care. FAST-Forward Boost shows there is a real appetite for research that could make a difference to current and future patients.
“We want to know whether a targeted integrated radiotherapy boost delivered in one week can still reduce the risk of breast cancer returning as well as the three-week treatment, without adding unnecessary treatment or side effects. If it does, the findings could help us deliver a future of shorter radiotherapy schedules, giving patients the treatment they need in a way that fits more easily into their lives.”
‘It could make a real difference to patients’
Dr Carmel Anandadas, Consultant Oncologist at The Christie and Clinical Coordinator of the FAST-Forward Boost trial, said:
“The trial has helped many centres implement integrated boost techniques alongside more closely aligning UK radiotherapy boost schedules. It has brought centres together to share expertise and refine practice around high-quality radiotherapy planning and delivery.
“That collaboration is one of the real strengths of the FAST-Forward Boost trial, and reaching 1,000 participants would not have been possible without the commitment of teams at hospitals across the UK and, most importantly, the women who have chosen to take part.”
“Clinical trials like FAST-Forward Boost are essential not only for improving treatment for people with cancer, but for finding better and more efficient ways of delivering care across the NHS.
“If we can show that radiotherapy can be delivered safely and effectively in five hospital visits rather than 15, it could make a real difference to patients and their families, cutting time and expense of travelling for treatment and time away from work while freeing up valuable NHS capacity.
“By testing new approaches rigorously and building the evidence needed to change clinical practice, research like this can improve outcomes for patients while helping to make our health service more productive.”
‘World beating research capabilities’
"This trial shows how the UK is using our world beating research capabilities to pursue huge improvements and transformations in cancer treatment for patients in our NHS.
“This programme is aiming to radically shorten the treatment times for breast cancer - to support patients and save more lives. The UK is home to some of the best medical research and clinical expertise in the world, and this trial is the latest example of what we can achieve when we bring them together."
“Playing a major role in tackling some of the biggest killers, including breast cancer, is at the very heart of what we do. For 20 years, the NIHR has invested in studies like the FAST-Forward BOOST trial – funding high-quality research that transforms patient care in the NHS.
“We know the impact breast cancer treatment can have on patients and their families, and how the side effects of radiotherapy can affect people’s quality of life, even long after treatment has ended. Studies like this are crucial, as they aim to not only identify new treatment options which can be delivered swiftly and safely – but also minimise side effects, giving patient more time away from hospitals and with the people that they love.”
‘Having fewer sessions helped me manage day-to-day life better’
Lucy Jackson is 34 and a mum of two young girls from Bolton. She is one of the women who benefitted from having five sessions of radiotherapy as part of the trial.
Lucy, who has been married to Callum for nearly four years and works in apprenticeships, was diagnosed with breast cancer in April 2025.
“My GP referred me to my local hospital for more tests. I didn’t really think anything of it, so it was quite a shock to be told I had cancer. My girls Annie and Rosie were only 8 and 3 at the time, so my thoughts immediately went to them and Callum.
“It’s important that people advocate for themselves when they go to the doctor. We know our bodies best and shouldn’t be afraid to push for more tests or investigations if we think we need them,” Lucy said.
Lucy’s tumour hadn’t spread and, following a successful operation to remove it, she was referred to The Christie’s local radiotherapy centre in Salford. It was at this point that she was told about the FAST-Forward Boost trial. She started her five days of treatment last autumn.
“I agreed to take part straight away,” she says. "I ended up having my radiotherapy over five days, which was great. I got no real side effects – I felt a bit tired, and that was it – and it meant I could finish my treatment much quicker,” she said.
“Having fewer sessions also helped me manage day-to-day life better. If the traffic was bad, it could take me about an hour each way to get to Salford, which is time away from Annie and Rosie, so being able to have fewer radiotherapy sessions meant less travel as well.”
Lucy is coming up to the first anniversary of the end of her cancer treatment, and all her recent scans show she is still cancer free.
“I’m the sort of person who just gets on with things, so I didn’t do anything special to celebrate the end of my treatment, but I’m now focussing on my life beyond cancer,” she said.
“I’m really glad to have taken part in the trial and have been approached to take part in another study since. I understand how important research is in terms of making things better for cancer patients, and I wanted to do my bit to help others like me in the future,” Lucy added.
Dr Catherine Elliott, Director of Research and Partnerships at Cancer Research UK, said:
"By 2040, around 70,000 women are expected to be diagnosed with breast cancer every year in the UK. Trials like this are driving vital improvements in the use of radiotherapy, helping to cut down treatment time in hospital.
"To ensure the UK remains a world-leader in cancer research, the UK Government must continue to invest in research like this and remove barriers slowing down clinical trials so life-saving tests and treatments can reach patients sooner."
‘It was a big relief’
Royal Marsden patient Sheena Ruscoe was 42 years old when she was diagnosed with breast cancer in 2024. After discovering a lump and visiting a breast clinic, she received surgery and chemotherapy at two local hospitals. Then, in 2025, Sheena came to The Royal Marsden and enrolled onto the FAST-Forward Boost trial.
Sheena said:
"I was initially booked to have radiotherapy at a local hospital, but the doctors saw that my heart is positioned too close to the rib cage and there were concerns that the radiotherapy would hit one of my heart valves. My oncologist suggested the FAST-Forward Boost trial, with the hope that it’s a lot more targeted and gentler due to having fewer sessions. I then spoke to Professor Anna Kirby and I felt reassured.
“I didn’t really know what to expect when I first arrived at The Royal Marsden. I had all my treatment in five days, and when I knew that’s what I was having, it was a big relief. The actual radiotherapy sessions were about 20 minutes, so not too long at all. It was all so seamless really and the staff were great.
“I have spoken to some people whose radiotherapy was longer. Anything that shortens that time is really appreciated. Travelling in every day from outside of London was tiring, but the fact that it was only for five days was a lot more manageable. Cancer is horrible and so anything that can ease the treatment is amazing."
Find out more about the FAST-Forward Boost trial.