A new National Cancer Institute (NCI) funded clinical trial (TAILORx) has revealed that the use of Oncotype DX Breast Recurrence Score can help 70% of hormone receptor (HR) positive, HER2-negative, axillary lymph node­-negative breast cancer patients to avoid chemotherapy and in turn its side-effects.

The score is a molecular test designed to analyse the expression of 21 genes associated with the cancer recurrence in order to determine the appropriate and effective post-operative treatment for women with this particular type of breast cancer.

Data from the Phase III TAILORx study found no benefit from the chemotherapy and hormone therapy combination after surgery when compared to treatment with only hormone therapy.

“The 21-gene expression test can be used to assess the risk of recurrence and remove the need for unnecessary treatment.”

The trial was performed with 10,273 subjects at 1,182 clinical centres across the US, Australia, Canada, Ireland, New Zealand and Peru.

During the study, patients’ tumours were tested using the Oncotype score, based on the range of which they were assigned a treatment.

Participants in low-risk range (0-10) were given only hormone therapy, while those in the high-risk received hormone therapy and chemotherapy. However, women in the intermediate range (11­–25) were randomly assigned to either one of these groups.

The primary objective of the trial was to investigate if hormone therapy alone can be comparable to outcomes from chemotherapy plus hormone therapy.

It was observed that overall survival with hormone therapy alone was 98% and patients who received both experienced 98.1%.

Based on these findings, the researchers concluded that chemotherapy may be avoided in the majority of HR-positive, HER2-negative, node-negative breast cancer patients.

The 21-gene expression test can be used to assess the risk of recurrence and remove the need for unnecessary treatment.

NCI Cancer Therapy Evaluation Program associate director Jeffrey Abrams said: “These findings, showing no benefit from receiving chemotherapy plus hormone therapy for most patients in this intermediate-risk group, will go a long way to support oncologists and patients in decisions about the best course of treatment.”

The results from the trial, which was designed and led by the ECOG-ACRIN Cancer Research Group, were reported at the American Society of Clinical Oncology (ASCO) annual meeting held in Chicago, US.