Millions of breast cancer patients could be spared chemotherapy thanks to a revolutionary new genomic test, according to a clinical trial. The most common cancer among women in the UK, breast cancer is typically treated by surgically removing tumours, followed by chemotherapy to prevent recurrence. However, chemotherapy can cause severe side effects including hair loss, nausea, insomnia, fatigue, infertility, and cognitive impairment.
Groundbreaking trial results
Doctors have long been concerned that many patients with hormone-sensitive breast cancer receive little or no benefit from chemotherapy yet still endure its significant and sometimes dangerous side effects. Now, a groundbreaking trial led by University College London (UCL) has shown that a genomic test called Prosigna can reliably determine which patients will benefit from chemotherapy and which will not.
The Optima trial involved more than 4,400 women and men aged 40 or older who had undergone surgery for hormone-sensitive breast cancer. All participants were considered at high risk of recurrence and would normally have been prescribed chemotherapy. They each took the Prosigna test, which measures the activity of genes involved in breast cancer growth.
Participants with a high score (above 60) received chemotherapy plus hormone therapy, while those with a low score (60 or below) were treated with hormone therapy alone. Among the low-scoring group who did not receive chemotherapy, outcomes were very similar to those who did: five years after treatment, 94.8% of those who had chemotherapy alongside hormone therapy were alive and free from recurrence, compared to 93.6% of those treated with hormone therapy alone.
Patient story: Karen Bonham
Karen Bonham, 64, from Cardiff, took part in the trial after being diagnosed with breast cancer in June 2017. She was days away from starting chemotherapy and had already cut her hair short when she learned she was in the group that could safely avoid it. "How to describe the initial feeling? Immense relief? Like Christmas? Certainly a mixture of the two," she said. Instead of chemotherapy, she received radiotherapy and hormone therapy. Nearly nine years later, she feels cancer no longer defines her and has returned to normal family life. She said the trial "helped decision making to allow me to receive targeted, appropriate treatment more quickly and has enabled my positive health outcome."
Implications and next steps
Researchers say the trial provides strong evidence that medics can "safely reduce" the use of chemotherapy for breast cancer patients worldwide. However, more research is needed to determine whether the test offers the same benefits for men and people under 40. Co-chief investigator Professor Iain MacPherson, professor of breast oncology at the University of Glasgow, said: "Optima provides robust, practice-changing evidence that we can safely reduce the use of chemotherapy for many patients with hormone-sensitive breast cancer. These findings represent a major step forward in delivering more personalised, precise care, ensuring that treatment decisions are driven by what will genuinely improve outcomes for patients, while avoiding unnecessary toxicity. The potential impact for both patients and health services is substantial."
