Test to detect if breast cancer will return ‘100 per cent accurate’

A blood test that can detect if breast cancer will return with “100 per cent accuracy” has been developed by scientists.

The “ultra-sensitive” test can predict a breast cancer relapse years before it would show up on NHS scans and could allow women to undergo early, life-saving treatment.

The test identifies cancer DNA in the blood, known as circulating DNA, that has survived previous rounds of treatment, but are “undetectable” to conventional scans.

Experts said the breakthrough could have a “transformative effect” on cancer treatment because “early detection is one of our greatest weapons” for improving survival rates.

In a trial by the Institute of Cancer Research (ICR) in London, 78 breast cancer survivors, who had all undergone surgery and chemotherapy to treat their initial cancer, were monitored for five years and had blood tests every six months.

The findings, which are being presented at the American Society of Clinical Oncology (Asco) in Chicago on Sunday, revealed that all 11 patients who had cancer DNA in their blood went on to have their tumour return.

Cells detected 15 months earlier

The test detected the presence of cancer cells in the blood 15 months before there were clinical signs of a relapse on average, with one woman having cancer DNA present three and a half years before a tumour returned.

All of those who did not have residue cancer cells continued to live cancer free during the study period, while three women tested positive for cancer DNA but did not relapse during the study period.

Dr Isaac Garcia-Murillas, the lead author from the molecular oncology group at the ICR said the test could identify breast cancer cells in the body that “are undetectable on follow-up scans”.

“These cells can cause breast cancer patients to relapse many years after their initial treatment,” he said. “Ultra-sensitive blood tests could offer a better approach for the long-term monitoring of patients whose cancer is at high risk of returning.”

Detecting the cancer cells early would allow women to undergo closer monitoring and treatment as soon as necessary, drastically reducing the risk that the disease spreads and becomes incurable.

There are 55,000 cases of breast cancer in the UK each year, making it the most common form of the disease, with about one in four patients suffering a relapse.