Many people with breast cancer can safely avoid chemotherapy with the use of a gene test, potentially sparing them unnecessary side effects without increasing the risk of the cancer returning, a large international clinical trial has found. The OPTIMA trial (Optimal Personalised Treatment of early breast cancer using Multi-parameter Analysis), led by UCL and involving researchers at the Institute of Genetics and Cancer, was designed to reduce the use of unnecessary chemotherapy for people with newly diagnosed breast cancer.It followed more than 4,400 patients across the UK, Norway, Sweden, Australia, New Zealand and Thailand.The findings, presented at 2026 American Society of Clinical Oncology (ASCO) meeting in Chicago in May, suggest that people aged 40 and over whose tumours have a low Prosigna test score can be treated safely with hormone therapy alone, potentially transforming care for thousands of patients each year. Drawbacks of chemotherapy Chemotherapy is regularly offered to people with early‑stage breast cancer that has spread from the breast to nearby lymph nodes, as it lowers the risk of the disease returning.While effective overall, there is concern among clinicians that many people with the most common, hormone‑sensitive type of breast cancer receive little or no benefit from chemotherapy but still experience its significant and sometimes dangerous side effects.OPTIMA set out to address this dilemma by using a genomic test from Veracyte called Prosigna, which measures the activity of genes involved in breast cancer growth.Unlike some similar tests, Prosigna can be run by NHS laboratories with the appropriate equipment.The test is performed on cancer tissue samples. Typically, these are tumours removed at surgery but as the test uses very little tissue, it also works on diagnostic needle biopsies. IGC researchers Dr Karen Taylor’s group has played a central role in the trial by curating the translational pathology biobank of UK samples for both OPTIMA and its preliminary phase, OPTIMA Prelim, since 2012.More recently they performed the retrospective processing of 2000 control arm samples and subsequent Prosigna testing which was key to the primary analysis. OPTIMA provides practice-changing evidence that many patients with the most common hormone-sensitive breast cancer can safely avoid chemotherapy without compromising outcomes. By using tumour biology to guide treatment decisions, the trial marks an important step toward more personalised, evidence-based care, reducing unnecessary side effects for patients. Dr Karen Taylor Research Fellow, Institute of Genetics and Cancer Meanwhile, Peter Hall’s group led the health economics data collection and analysis part of the trial. The OPTIMA trial results will re-define the cost-effectiveness model for early breast cancer management. By establishing that genomic profiling can safely de-escalate treatment for the estimated two-thirds of node-positive patients who derive no benefit from chemotherapy, the financial implications for public healthcare systems like the NHS are substantial. The upfront cost of the diagnostic test is heavily outweighed by the immediate savings from avoided chemotherapy and the long-term reduction in managing treatment-induced toxicities, all whilst releasing vital clinical capacity back into overstretched oncology units. The magnitude of these benefits will be formally qualified in our within-trial health economics analysis. Professor Peter Hall Senior Clinical Lecturer in Cancer Informatics Related links Karen Taylor’s Research Group Peter Hall’s Research Group Photo: National Cancer Institute on Unsplash Tags 2026 Publication date 29 May, 2026
