Prof John Yarnold speaks about his research into hypofractionation radiotherapy as a treatment for women with early breast cancer. This technique allows clinicians to considerably reduce the number of daily treatment sessions and treatment duration. Prof Yarnold also discusses partial breast radiation, the lack of mature clinical trial data to support this technology and warns patients of the risks of receiving this treatment outside of clinical trials. Prof Yarnold concludes by suggesting why there is currently a lack of clinical studies comparing the efficacy of new radiosurgery technologies.