Gene test could spare around 5,000 breast cancer patients a year from chemotherapy

A genomic test that reads the activity of dozens of genes inside a tumour could allow thousands of breast cancer patients to safely skip chemotherapy each year, according to results from a large international trial coordinated in the UK. The findings, from the OPTIMA study, were presented at the American Society of Clinical Oncology annual meeting in late May and have been described by oncologists as a meaningful step towards more personalised cancer care.

The trial focused on people with hormone receptor-positive, HER2-negative early breast cancer that had spread to the lymph nodes under the arm. This is normally considered higher risk, and patients in this category are routinely offered chemotherapy alongside hormone therapy. Because lymph node involvement has long been treated as a signal that cancer cells may have begun to travel beyond the breast, clinicians have tended to err on the side of more intensive treatment.

The OPTIMA results challenge that blanket approach. By looking at the underlying biology of each tumour rather than relying on its size or spread alone, researchers were able to separate patients who genuinely need chemotherapy from those for whom it adds toxicity without measurably improving their odds. The information in this article is general in nature and should not be taken as personal medical advice; treatment decisions are made by clinicians in consultation with each patient.

How the test works

Researchers used the Prosigna test, which measures the activity of 50 genes linked to cancer growth and generates a risk-of-recurrence score. Rather than asking simply how far a cancer has spread, the test asks how aggressively the tumour is behaving at a molecular level. Patients whose tumours returned a low score were assigned to hormone therapy alone, while those with higher scores received chemotherapy followed by hormone therapy.

The trial enrolled around 4,400 participants aged 40 and over across more than 170 hospitals in the UK and several other countries. That scale matters: large, multi-centre trials make it more likely that the findings will hold true across the diverse population the NHS actually treats, rather than reflecting the experience of a single specialist unit.

More than two-thirds of participants, some 68 per cent, fell into the low-score group. Among them, five-year recurrence-free survival was almost identical whether or not they had chemotherapy: 94.8 per cent for those who received it, against 93.6 per cent for those who did not. In other words, for this group the addition of chemotherapy made little measurable difference to the risk of the cancer returning within five years.

“We can use a tumour's biology to confidently identify many patients who can be spared chemotherapy and its side effects, without compromising their chances of staying free of cancer.”

— Professor Rob Stein, Chief Investigator, UCL

Why sparing chemotherapy matters

Chemotherapy is a powerful and often life-saving treatment, but it is also indiscriminate, attacking healthy fast-dividing cells alongside cancerous ones. For patients who derive little benefit, the costs can be considerable. Researchers and clinicians point to a range of short and long-term burdens that can be avoided when chemotherapy is safely omitted.

• Acute side effects such as hair loss, severe fatigue, nausea and a heightened risk of infection
• Longer-term complications including nerve damage, heart problems and, in rare cases, secondary cancers
• The possible impact on fertility for younger patients
• Months of disruption to work, family life and wellbeing during and after treatment
• The financial and logistical strain of repeated hospital visits and recovery time

Avoiding unnecessary treatment also frees up NHS capacity. Each course of chemotherapy requires chair time in busy day units, pharmacy preparation and close monitoring. Reducing the number of patients who need it could ease pressure on cancer services that have struggled with backlogs and staffing shortages in recent years.

Background and context

The OPTIMA trial is part of a broader shift in oncology towards what is sometimes called de-escalation: giving patients the least intensive treatment that still delivers the best outcome. For decades, breast cancer care has been moving away from one-size-fits-all regimens towards therapy tailored to the genetic and molecular profile of an individual tumour. Genomic tests are already used in some lower-risk breast cancers to guide chemotherapy decisions, but their role in node-positive disease has been less clear.

The study was led by University College London and the University of Glasgow, with trial coordination by the University of Warwick. It was supported by public and charity funding, reflecting a long-running collaboration between UK academic centres and the NHS that has placed Britain at the forefront of practice-changing cancer trials.

Breast cancer remains the most common cancer in the UK, with tens of thousands of new diagnoses every year. The majority of cases are hormone receptor-positive, meaning the findings could be relevant to a substantial proportion of patients, even though the trial focused on a specific higher-risk subgroup.

“For many women, the prospect of avoiding months of chemotherapy without raising the risk of their cancer coming back is genuinely life-changing.”

— A consultant oncologist not involved in the trial

What happens next

Researchers estimate that around 5,000 NHS patients a year could be spared chemotherapy on the basis of these findings. The next step will be assessing how the Prosigna test can be adopted into routine NHS practice, including how it is funded, which laboratories will run it and how quickly results can be returned to inform treatment decisions.

Health technology assessments and clinical guidelines will need to be updated before the approach becomes standard, and clinicians caution that the test is a tool to support shared decision-making rather than a replacement for individual judgement. For now, patients are advised to discuss their own circumstances with their cancer team, who can explain whether genomic testing is appropriate for them.