Daijiworld Media Network – London

London, May 31: A new DNA-based test could spare millions of breast cancer patients worldwide from undergoing chemotherapy, according to findings from a major international study that researchers say could transform cancer treatment.

The study, led by University College London (UCL), found that more than two-thirds of breast cancer patients could safely avoid chemotherapy and be treated with hormone therapy alone without compromising survival rates.

Researchers analysed more than 4,000 newly diagnosed breast cancer patients aged over 40 from the United Kingdom, Norway, Sweden, Australia, New Zealand and Thailand.

Scientists used a genomic test known as Prosigna, which measures the activity of 50 genes linked to breast cancer growth and estimates the risk of the disease returning. Patients who received a low-risk score, accounting for around two-thirds of participants, did not undergo chemotherapy.

The study found that the five-year survival rate among patients who avoided chemotherapy was 93.7 per cent, compared to 94.9 per cent among those who received the treatment as part of their care.

Breast cancer treatment typically involves surgery to remove tumours, followed by chemotherapy to reduce the risk of recurrence. Chemotherapy is also commonly recommended for patients with early-stage breast cancer that has spread to nearby lymph nodes.

However, researchers said the treatment often offers limited benefit to many patients with the most common form of breast cancer while exposing them to significant side effects, including fatigue, nausea, hair loss, weakened immunity and fertility problems.

According to UCL, the findings could allow more than 5,000 patients annually under the UK's National Health Service (NHS) to avoid unnecessary chemotherapy.

Karen Bonham, a 64-year-old participant from Cardiff, described the results as an "immense relief". She avoided chemotherapy after receiving a low-risk score from the Prosigna test and instead underwent radiotherapy and hormone therapy over the past eight years.

"Cancer diagnosis and treatment can be shocking. It certainly propels you into a world of uncertainty. Life priorities realign — you simply want to survive," she said.

The findings were presented at the annual meeting of the American Society of Clinical Oncology in Chicago, the world's largest cancer conference.

Professor David Miles, a leading cancer specialist involved in the research, described the results as "practice-changing". He said the test enables doctors to accurately identify patients who would gain little or no benefit from chemotherapy and spare them the physical and emotional burden of the treatment.

He noted that doctors previously administered chemotherapy to large numbers of patients knowing only a small proportion would derive significant benefit.

Another breast cancer patient, Tanya Hutson, who underwent chemotherapy after her diagnosis in 2022, welcomed the breakthrough and described the treatment as "brutal".

She said the new test demonstrates the value of medical research and could prove to be a major breakthrough for patients who might otherwise undergo unnecessary chemotherapy.

Researchers cautioned that it remains unclear whether the findings apply to patients under the age of 40, with further studies expected to provide answers in the coming years.