How a New DNA Test Could Help Breast Cancer Patients Avoid Chemotherapy Completely

Last Updated:May 30, 2026, 16:15 IST

The findings come from an international clinical trial involving more than 4,000 newly diagnosed breast cancer patients aged over 40 across six countries.

Millions of breast cancer patients could one day be spared chemotherapy thanks to a DNA-based test that helps doctors identify who is most likely to benefit from the treatment and who may safely avoid it, according to new research. The findings come from an international clinical trial involving more than 4,000 newly diagnosed breast cancer patients aged over 40 across six countries. Researchers found that more than two-thirds of participants could forgo chemotherapy without significantly affecting their chances of survival.

How The DNA Test Works?

The study, led by researchers at University College London (UCL), used a gene test known as Prosigna to analyze the activity of 50 genes linked to breast cancer growth. The test generates a score that estimates a patient’s risk of the cancer returning after initial treatment. Patients classified as low risk based on the test results were treated with hormone therapy rather than chemotherapy. After five years, the survival rate among those patients was 93.7%, compared with 94.9% among patients who received chemotherapy as part of their treatment.

Researchers say the findings highlight the growing role of personalized medicine in cancer care, allowing treatment decisions to be guided by the biology of a patient’s tumor rather than broad clinical characteristics alone.

Why Reducing Chemotherapy Matters?

Chemotherapy remains a standard treatment for many breast cancer patients following surgery because it can reduce the risk of recurrence. However, it is also associated with significant side effects, including fatigue, nausea, hair loss, weakened immunity and fertility problems. The ability to identify patients unlikely to benefit from chemotherapy could spare thousands from those physical and emotional burdens. According to UCL, more than 5,000 patients treated by England’s National Health Service each year could potentially avoid chemotherapy if the findings are incorporated into routine care.

Professor Rob Stein, chief investigator of the trial and professor of breast oncology at the UCL Cancer Institute, said the research marks a significant step toward more individualized 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," Rob Stein said.

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