Millions with Breast Cancer May Avoid Chemotherapy Thanks to New DNA Test

Millions of women diagnosed with breast cancer may be able to avoid the debilitating side effects of chemotherapy, thanks to a new DNA test developed by scientists. The Prosigna test can distinguish between patients who will likely benefit from chemotherapy and those who will not, potentially sparing many from harsh treatments.

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Millions of people with breast cancer could safely avoid chemotherapy, as scientists have developed a DNA test that can distinguish patients who are likely to benefit from treatment from those who will not.

An international study involving over 4,000 newly diagnosed patients aged 40 and above across the UK, Norway, Sweden, Australia, New Zealand, and Thailand revealed that more than two-thirds of participants could safely forgo chemotherapy. These individuals could instead be treated with hormone therapy alone. Chemotherapy can lead to severe side effects, including fatigue, nausea, hair loss, a weakened immune system, and fertility issues.

The study, led by University College London (UCL), used the Prosigna gene test to measure the activity of 50 genes involved in breast cancer growth. This allowed researchers to calculate a patient's risk of the disease returning. Those who received a low score, representing two-thirds of the group, did not undergo chemotherapy. Their five-year survival rate was 93.7%, only slightly lower than the 94.9% survival rate for patients who did receive chemotherapy.

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The results are a huge relief.

Researchers at UCL noted that this approach could potentially allow over 5,000 NHS patients annually to avoid chemotherapy. Karen Bonam, a trial participant from Cardiff, described the results as a "huge relief." Having avoided chemotherapy herself, she received eight years of radiotherapy and hormone therapy. The study's lead investigator, Professor Rob Stein, highlighted the findings as a significant step toward more personalized treatment, stating, "For patients, this means many can 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."

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The study has successfully used tumor biology to inform decisions, rather than relying solely on traditional clinical characteristics. For patients, this means many can 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.