One-week breast cancer radiotherapy proven as safe and effective as standard three-week treatment, suggests study

Presented at ESTRO 2025, which gathered a record attendance of 7,908 participants this week in Vienna, Austria, a 10-year study, involving over 4,000 UK patients, confirms that a one-week course of post-surgery radiotherapy is just as safe and effective as the traditional three-week regimen for early-stage breast cancer patients. These long-term results from the FAST-Forward trial, could further reduce the burden on breast cancer patients worldwide, and expand access to life-saving radiotherapy.

The phase III randomised trial, which was sponsored by The Institute of Cancer Research, London and funded by a grant from UK National Institute of Health Research (NIHR), followed up patients for ten years and showed that a shorter, five-day radiotherapy schedule provides a similar level of cancer control as the standard 3-week treatment, without additional long-term side effects. This builds on previous five-year results that have already led to a shift in clinical practice.

Why This Matters

Breast cancer is one of the most common cancers globally, and radiotherapy plays a critical role in reducing the risk of recurrence after surgery. A shorter treatment course offers major benefits:

• More convenient for patients, reducing hospital visits

• Reduces pressure on radiotherapy services, making treatment more accessible

• Same safety and effectiveness as the longer regimen

“This 10-year analysis provides definitive long-term evidence that one-week radiotherapy to the breast is a safe, effective, and more practical option for breast cancer patients,” said Professor Murray Brunt, lead investigator of the study.

Professor Judith Bliss, Professor of Clinical Trials at The Institute of Cancer Research, London, who co-led the trial, said:

"The FAST-Forward trial revolutionised cancer treatment by reducing the standard radiotherapy from three weeks to just one week, without compromising effectiveness.

“This approach has significantly improved patient experience and healthcare practices, both during and after the Covid-19 pandemic, by minimising hospital visits.

“The streamlined schedule has made radiotherapy more accessible to more women, particularly those who are less able to attend hospital and those from lower-income countries.”

Professor Matthias Guckenberger, President of ESTRO, Chairman of the Department of Radiation Oncology and full Professor at the University Hospital Zurich and University of Zurich, emphasised the broader significance of this research:

"Radiotherapy is a cornerstone of modern cancer treatment, and studies like FAST-Forward demonstrate how we can optimise its delivery to benefit more patients.

“By reducing treatment time without compromising effectiveness, we are not only improving patient experience but also making better use of radiotherapy resources and healthcare systems worldwide.”

“These findings reinforce the critical role of radiotherapy in the fight against cancer."

Reference:

One-week breast cancer radiotherapy proven as safe and effective as standard three-week treatment in 4,000-patient study over 10 years, European Society for Radiotherapy and Oncology (ESTRO), Meeting: ESTRO 2025.