Significant scientific advancements indicate the potential for a simple blood test to detect relapse risks in certain breast cancers.

This development is central to discussions at the 61st annual meeting of the American Society of Clinical Oncology (ASCO), taking place in Chicago from May 30 to June 3. Professor François-Clément Bidard from the Curie Institute, a key figure in this research, emphasized the importance of this 'new concept' during a press briefing.

He is the lead author of a paper published in the New England Journal of Medicine that also discusses a new drug, camizestrant, developed by AstraZeneca.

The technology, known as 'liquid biopsy' or 'circulating tumor DNA' (ctDNA) analysis, allows for cancer monitoring through blood tests rather than traditional biopsies, which involve more invasive procedures that extract tissue samples.

This method detects tumor-derived DNA in the bloodstream, providing critical genetic information about the cancer's evolution.

This promising approach could lead to early, non-invasive interventions that may prevent relapses in women with hormone-dependent breast cancers, the most common type of breast tumors, especially in metastatic cases.

Currently, women diagnosed with hormone receptor-positive metastatic breast cancer receive treatment via a combination of medications that includes hormone therapy to reduce estrogen production (aromatase inhibitors) and agents that inhibit cell proliferation (CDK4/6 inhibitors).

However, approximately 40% of these patients experience mutations in the gene responsible for the estrogen receptor (ESR1), leading to resistance to hormone therapy and subsequent cancer relapse.

The blood test aims to identify these mutations months before they might cause cancer progression, enabling the possibility of adjusting hormone therapies or combining them with cell cycle inhibitors to mitigate the risk of tumor advancement.

The findings were previously supported by a French academic trial (Pada-1) led by Professor Bidard in the fall of 2022, and further validated by an international Phase III clinical trial (Serena-6) of AstraZeneca’s camizestrant.

In this study, nearly 3,000 patients were monitored through blood tests every two to three months.

Among them, 315 developed mutations detectable in their blood without evidence of cancer's advancement, and these participants were divided into two groups.

One group continued standard treatment, while the experimental group received camizestrant alongside a cell cycle inhibitor.

Patients receiving the novel oral treatment experienced a 56% reduction in their risk of cancer progression, extending the time until initial progression by approximately six months.

After 12 months, the progression-free survival rate was reported at 60.7% for those treated with camizestrant, compared to 33.4% for standard treatment.

At the 24-month mark, progression-free survival rates stood at 29.7% versus 5.4%, as detailed in a statement from the Curie Institute.

This marks a pioneering step in breast cancer management and may have broader applications in oncology.

Professor Bidard noted that this reflects 'the first time the pharmaceutical industry recognizes the potential of liquid biopsy for receiving health authorities' approval for new treatments, indicating that other companies are likely to explore this innovative approach to initiate therapies.'

As the global incidence of hormone-dependent breast cancer continues to increase, competition intensifies among pharmaceutical companies to develop next-generation hormone therapies.

AstraZeneca has positioned camizestrant as a first-line treatment, seeking to distinguish itself amidst rivals such as Roche, Pfizer, and Eli Lilly, who are also conducting studies in this therapeutic area.

Public health data reveal that breast cancer remains the most prevalent and deadliest cancer among women.

In 2018, it accounted for 12,146 deaths, with 61,214 new cases reported annually according to 2023 statistics.