The OPTIMA trial, coordinated for delivery and data analysis by the University of Warwick, and sponsored by University College London (UCL), followed more than 4,400 patients across the UK and internationally. Its findings, being presented at the American Society of Clinical Oncology (ASCO) annual meeting, could spare many NHS patients a year from unnecessary 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.
Adrienne Morgan (co-founder of Independent Cancer Patients' Voice) knows the impact of chemotherapy on breast cancer patients first-hand; she underwent the treatment herself after a diagnosis of hormone-sensitive breast cancer before trials like OPTIMA existed. As the patient and public involvement representative working alongside the Warwick team, she said: "The OPTIMA trial was urgently needed to prevent patients being subjected to treatment, which is dangerous and distressing, and to reduce unnecessary costs in the NHS. If I had known then what I know now I am fairly sure that I would have declined chemotherapy."
The trial used a genomic test called Prosigna, which measures the activity of genes that influence breast cancer growth. Unlike some comparable tests, Prosigna can be run by NHS laboratories that have the required equipment and works on tissue already removed during routine biopsy or surgery.
Patients aged 40 years or older who joined the trial after surgery were randomly assigned either to receive standard chemotherapy followed by hormone therapy, or to have their treatment guided by the Prosigna test. Those with a low-test score in this group didn't have chemotherapy and received hormone therapy alone; those with a high score received the same treatment as the standard group.
More than two thirds (68%) of patients in the Prosigna group had a low Prosigna score. For these patients, outcomes after five years were very similar whether they had chemotherapy or not. 93.6% of those who skipped chemotherapy were alive and free from recurrence, compared with 94.8% of those who received it.
These findings indicate that using the Prosigna test to guide treatment decisions could help a substantial number of patients avoid unnecessary chemotherapy without compromising their outcomes. Statistical analysis suggests that at the most only 2% of patients with a low score may benefit from chemotherapy. Many NHS patients diagnosed with early breast cancer every year with hormone sensitive breast cancer could avoid chemotherapy because of this trial.
Professor Janet Dunn, Head of Cancer Trials at Warwick Clinical Trials Unit said: "This is a fantastic result for the OPTIMA team as we can safely identify patients with a low Prosigna test score who can forego chemotherapy in this higher risk patient group. Patients will be delighted with these results."
Karen Bonham, 64, from Cardiff, was one of the first patients to join the trial after being diagnosed following routine screening in 2017. After surgery revealed a large tumour with two affected lymph nodes, chemotherapy was the standard next step, and Karen was already dreading it. "Cancer diagnosis and treatment can be shocking," she said. "It certainly propels you into a world of uncertainty."
She had already cut her hair short in preparation for treatment when, just over two weeks after her Prosigna test, she received a call while walking on a local beach to say her low score meant she did not need it. "How to describe the initial feeling? Immense relief? Like Christmas? Certainly, a mixture of the two." Instead, she went on to receive radiotherapy and hormone therapy. Now almost nine years on, Karen has returned to normal family life, remaining active with walking and yoga.
Chief Investigator of the OPTIMA trial and Professor of Breast Oncology at the UCL Cancer Institute, Professor Rob Stein said: "OPTIMA addresses a long-standing challenge in breast cancer care: identifying who truly benefits from chemotherapy and who does not. Our findings show that many patients can safely avoid chemotherapy without compromising their outcomes.
These results mark an important and significant step toward more personalised treatment. The trial has successfully used tumour biology to guide decisions rather than relying solely on traditional clinical features. For patients, this means many may be spared the physical and emotional burden of chemotherapy and its potential long-term side effects. For health systems, it represents a more efficient and evidence-based use of resources."
The results are expected to inform guidance from the National Institute for Health and Care Excellence (NICE) on wider NHS access to Prosigna testing.
