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Post-operative avoidance of radiotherapy: biomarker selection of women categorised to be in a very low risk group by IHC4+C.

Disease site: Breast cancer

Treatment modality: Radiotherapy

Status: Open to recruitment

Trial details

PRIMETIME is a phase III, multicentre trial which tests whether radiotherapy can be safely avoided in patients considered to have such a low risk of local recurrence that the potential absolute gain from radiotherapy does not outweigh the established risks associated with breast radiotherapy.

PRIMETIME will use immunohistochemical biomarkers with clinical information (IHC4+C) to direct selective avoidance of breast radiotherapy. The IHC4+C algorithm will be used to risk stratify patients into a very low risk group (recommended avoidance of radiotherapy) or not (standard radiotherapy). 

Approximately 2,400 patients will be registered over four years to recruit 1,500 patients in the no radiotherapy group. All patients will be followed up for 10 years. 

Further information

Chief InvestigatorDr Charlotte Coles, The University of Cambridge

ICR-CTSU Scientific Lead: Professor Judith Bliss

Trial management contact: [email protected]

ISRCTN: 41579286

Sponsor: The Institute of Cancer Research (ICR)

Funding: Cancer Research UK

Links to PRIMETIME on the UK Clinical Trials Gateway and a plain English summary from Cancer Research UK will be added once available.

PRIMETIME Study video

We have produced a video for patients who have been invited to take part in the PRIMETIME study. The video is supplemental to the PRIMETIME main study patient information sheets and decision aid diagrams provided to eligible patients by their study doctor or nurse. Please make sure that you have read the PRIMETIME main study patient information sheets and decision aid diagrams before you watch this video. The video is designed to build on the information you have already received from your doctor. Please contact your breast cancer team with any questions about the PRIMETIME study. 

What the PRIMETIME video at

Publications and presentations

C.C. KirwanC.E. Coles, J. Bliss, On Behalf of the PRIMETIME Protocol Working Group; It's PRIMETIME. Postoperative Avoidance of Radiotherapy: Biomarker Selection of Women at Very Low Risk of Local Recurrence

Clinical trials

Division of Clinical Studies

The division carries out or coordinates high-quality trials and translational research at both an early phase – typically to test new targeted drugs – and a later stage.