Breast cancer: new kind of blood test could predict recurrence

Researchers have unveiled a new blood test capable of predicting the return of breast cancer several months, or even years, before a recurrence.

Their findings were presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

The researchers are still in the early stages of their work, but their findings nevertheless represent a major advance in breast cancer research.

A team of scientists from London’s Institute of Cancer Research (ICR) conducted a trial confirming the efficacy of this new kind of “ultrasensitive” blood test, as they explain in a news release.

Indeed, this discovery has the potential to lay “the groundwork for better post-treatment monitoring and potentially life-extending treatment in patients,” they say.

In other words, the earlier a recurrence is detected, the sooner treatment can be started to increase the chances of recovery.

According to the findings presented, this test is, more precisely, “an ultrasensitive liquid biopsy to detect the presence of tiny amounts of cancer DNA left in the body following treatment for early breast cancer”.

In their trial, presented at the 2024 ASCO Annual Meeting – one of the world’s largest cancer research conferences – the scientists reported that they were able to identify patients who subsequently relapsed, and therefore needed preventive treatment.

This is not the first time that researchers have raised the possibility of using such a test to predict a recurrence, but according to the scientists behind this research, their test promises to be much more sensitive, as it is based on a technique capable of identifying up to 1 800 mutations linked to the disease.

“Breast cancer cells can remain in the body after surgery and other treatments but there can be so few of these cells that they are undetectable on follow-up scans.

These cells can cause breast cancer patients to relapse many years after their initial treatment.

Ultrasensitive blood tests could offer a better approach for the long-term monitoring of patients whose cancer is at high risk of returning,” says the study’s first author, Dr Isaac Garcia-Murillas, of The Institute of Cancer Research, London.

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Improving early detection of cancer recurrence

To reach their conclusions, the researchers analysed blood samples from 78 patients with different types of early breast cancer, taken at the time of diagnosis, after the second cycle of chemotherapy, after surgery, and then every three months during the first year of follow-up.

Samples were subsequently taken at a reduced frequency of every six months for five years.

The aim was to detect the presence of circulating tumour DNA (ctDNA), a biomarker derived from cancer cells.

The scientists observed an association between the detection of ctDNA after surgery or during the follow-up period and an increased risk of recurrence and lower overall survival.

They also identified the 11 patients who went on to relapse thanks to this ultrasensitive blood test, at an average of 15 months before symptoms appeared or it was visible on scans.

However, the scientists say that detection as much as 41 months – or more than three years – before recurrence was the earliest they achieved. The researchers point out, however, that three patients for whom ctDNA was detected during follow-up did not relapse by the time the study period ended.

“Early detection is one of our greatest weapons against breast cancer and these initial findings, which suggests new tests could be able to detect signs of breast cancer recurrence over a year before symptoms emerge, are incredibly exciting,” says Dr Simon Vincent, director of research, support and influencing at Breast Cancer Now, which part-funded this study.

“While this research is still in its early stages, catching breast cancer recurrence earlier means treatment is much more likely to destroy the cancer and stop it spreading to other parts of the body, at which point it becomes incurable.”

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