Targeted radiotherapy cuts breast cancer side effects

Targeted radiotherapy is as effective as full-breast treatment for low-risk breast cancer but causes fewer side effects, a decade-long UK study has found.

Partial-breast radiotherapy, which directs radiation only to the area around the tumour rather than the entire breast, reduced long-term complications while maintaining a 3 per cent recurrence rate.

More than 9,000 women in the UK each year—about one in four patients needing radiotherapy after surgery—could benefit from the approach.

Researchers from the University of Cambridge and the Institute of Cancer Research followed over 2,000 women at 30 radiotherapy centres in the UK for 10 years as part of the IMPORT LOW trial.

The trial compared three techniques: whole-breast radiotherapy, partial-breast radiotherapy, and partial-breast radiotherapy with a reduced dose to tissue further from the tumour.

All three were equally effective at preventing cancer recurrence.

Only 15 per cent of those treated with partial-breast radiotherapy reported noticeable changes in breast appearance at five years, compared with 27 per cent who received whole-breast treatment.

Professor Charlotte Coles is professor of breast cancer clinical oncology at the University of Cambridge and chief investigator of the study.

The researcher said: “The IMPORT LOW trial has transformed how we treat early breast cancer, offering women a safer and effective option while significantly reducing some side effects.

“By targeting the area around the tumour, rather than the whole breast, we have demonstrated that patients can achieve the same outstanding long-term outcomes with fewer complications.

“This approach is now widely adopted across the NHS, sparing thousands of women from unnecessary radiation exposure.

“The results of this study have not only shaped UK clinical practice but also informed international guidelines, ensuring that women worldwide benefit from this personalised, evidence-based treatment.”

Following the trial’s success, partial-breast radiotherapy has been integrated into NHS guidelines and endorsed by the Royal College of Radiologists and the Association of Breast Surgery.

Since 2020, it has been delivered in five sessions instead of 15—making it less burdensome for patients and reducing cost.

The IMPORT LOW findings have also helped shape international guidelines, including those published in 2022 by the European Society of Radiation Oncology and in 2023 by the American Society for Radiotherapy and Oncology.

Dr Dani Edmunds, research information manager at Cancer Research UK, said: “This study shows that we can safely reduce the amount of radiotherapy we give to many women with early breast cancer without increasing the risk of the disease coming back.

“This means people experience fewer long-term side effects, like changes in how their breasts look or feel, making the treatment kinder.

“At Cancer Research UK, we’ve been investigating the use of radiotherapy in cancer medicine for more than 100 years, but it’s far from old-fashioned. This work shows how research is continuing to refine, improve and innovate the treatment so people can live longer, better lives.”

Experts estimate that between 25 and 30 per cent of breast cancer patients are eligible for partial-breast radiotherapy, and that approximately 74,000 women have already benefited from it.