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Breakthrough DNA test reduces chemotherapy use in breast cancer patients
A new gene test can identify breast cancer patients who can safely skip chemotherapy, sparing millions from its harsh side effects while maintaining high survival rates, an international study reveals.
Study findings
The trial, led by University College London (UCL), involved over 4,000 women aged 40 and above from six countries, including the UK, Australia, and Thailand. Researchers used the Prosigna test to analyze the activity of 50 genes linked to breast cancer growth, assigning patients a risk score for recurrence.
Two-thirds of participants-those with low scores-avoided chemotherapy and received hormone therapy alone. Their five-year survival rate reached 93.7%, nearly matching the 94.9% rate of patients who underwent chemotherapy.
Impact on treatment
Breast cancer treatment typically begins with surgery to remove tumors, followed by chemotherapy to reduce recurrence risk. However, clinicians have long suspected that many patients with the most common type of breast cancer gain little benefit from chemotherapy.
UCL estimates the test could spare more than 5,000 NHS patients annually from unnecessary chemotherapy, which can cause fatigue, nausea, hair loss, immune suppression, and fertility issues.
Patient experiences
Karen Bonham, 64, from Cardiff, participated in the trial and avoided chemotherapy after the Prosigna test deemed it unnecessary. She received radiotherapy and hormone therapy instead and described the results as an "immense relief."
"Cancer diagnosis and treatment can be shocking. It propels you into a world of uncertainty. Life priorities realign-you simply want to survive."
Karen Bonham, trial participant
Tanya Hutson, diagnosed in 2022, underwent chemotherapy and called the test "absolutely amazing."
"For all these people out there who don't need it but are still getting it-it's an absolute game changer."
Tanya Hutson, breast cancer survivor
Expert reactions
Professor David Miles, a leading cancer specialist, hailed the findings as "practice-changing" during an interview with BBC's Newshour.
"We can now confidently predict many patients will get no benefit at all, and therefore there's no need for them to have the chemotherapy. We used to give chemotherapy to 100 women to benefit 10, knowing that 90 didn't need it."
Professor David Miles, cancer specialist
Limitations and next steps
The study's results, presented at the American Society of Clinical Oncology's annual meeting in Chicago, do not yet apply to patients under 40. Further research is expected to take several years.
Hutson emphasized the importance of continued investment in medical research, calling the test a testament to its value.
