Expert is an investigator-initiated trial that aims to determine whether a genomic test of breast cancer tumour tissue can be used to identify patients who have a very low risk of cancer recurrence and can safely avoid radiation therapy (RT) after breast cancer surgery without increasing this risk.

Radiation therapy given together with endocrine therapy is currently the standard of care for patients with early breast cancer who underwent breast cancer surgery. However, the real benefit of radiation treatment may vary substantially from one patient to another, and patients with a low risk of recurrence may be overtreated and exposed to unnecessary treatment side effects.

De EXPERT trial is a unique opportunity to improve personalised use of radiation therapy in patients with early breast cancer according to their individual risk of cancer recurrence.

For every patient, a tumour sample collected from the breast cancer surgery is submitted to the Prosigna Breast Cancer Gene Signature Assay (PAM50), a validated genomic test which examines the type and level of gene expression in the tumour and determines the likelihood of cancer recurrence on a 1 to 100 score scale.

Patients with a risk score of 60 or less are eligible in the study and are randomised in one of these two arms:

• arm A: radiotherapy (RT) and endocrine therapy (standard of care)
• arm B: no RT; endocrine therapy alone (investigational arm)

Patients who have a higher score will continue with treatment off study in consultation with their clinician.

If the trial shows that omission of RT after breast cancer surgery and adjuvant endocrine therapy does not significantly increase cancer recurrence and mortality in the study population (investigational arm), this could lead to substantial impact on clinical care and health care costs.

In total 1,170 patients with luminal A early breast cancer aged 50 years and older will be randomised.

This study is coordinated and sponsored by the Breast Cancer Trials – Australia & New Zealand (BCT-ANZ) in collaboration with the Breast International Group (BIG) Headquarters

The study was opened to recruitment in Australia and New Zealand in 2017. It opened in Rest of World in July-August 2021.

Not at present

Breast Cancer Trials – Australia & New Zealand (BCT-ANZ) (sponsor) and the National Health and Medical Research Council of Australia, Loterie Nationale (Belgium), plus funds raised by the BIG HQ philanthropy team.

NCT02889874