31 March 2018


The purpose of this study is to see whether a specialised laboratory test (Prosigna (PAM50) Assay) of breast cancer tissue can be used to choose wāhine / women who can safely avoid radiation therapy because there is a low risk of the cancer coming back.

The EXPERT trial presents a unique opportunity to improve personalised use of radiation therapy in patients with early breast cancer according to their individual risks of local recurrence.

Scientific Title

Protocol ANZ 1601/BIG 16-02: A randomised phase III trial of adjuvant radiation therapy versus observation following breast-conserving surgery and endocrine therapy in patients with molecularly characterised luminal A early breast cancer.


The current standard of care for patients with early breast cancer after breast conserving surgery is hormonal therapy (if HR-positive) and also radiation therapy to the breast to improve local control and survival. However, breast cancer is a complex disease and the benefit of radiation therapy in individual patients varies substantially. Radiation therapy may not be needed for some women with certain types of early breast cancer.

Using the current breast radiotherapy may potentially lead to overtreatment for a proportion of women, and unnecessary treatment toxicity, financial costs and logistical challenges.

If doctors could identify (using the Prosigna PAM50 assay) women who have a very small risk of the cancer coming back, these women may not need radiation therapy and could avoid its side effects.

Enrolment: Open

EXPERT is an international clinical trial, let by Breast Cancer Trials. It will enrol 1170 patients and is open to wāhine / women aged 50 years or older, with Hormone Receptor (HR) positive, Human Epidermal Growth Factor Receptor 2 (HER2) negative, early-stage breast cancer.

Ask your Breast Surgeon or Oncologist if this trial is suitable for you.