Blood test may help guide cancer treatment for older women

A blood test could help guide breast cancer treatment for women aged 70 and over, a small study suggests.

Researchers analysed blood samples from women with oestrogen receptor-positive breast cancer, a common type fuelled by the hormone oestrogen, who were considering endocrine therapy as their main treatment while forgoing surgery and radiation.

Endocrine therapy works by blocking hormones, while the test looks for circulating tumour DNA, or ctDNA, which are tiny fragments of genetic material shed by cancer cells into the bloodstream. Researchers wanted to see whether these fragments could help identify patients unlikely to respond to endocrine therapy alone.

The study, carried out by scientists at UPMC Hillman Cancer Center and the University of Pittsburgh School of Medicine, found that patients whose ctDNA test was negative, either at the start of treatment or after beginning endocrine therapy, were more likely to have stable disease or tumour shrinkage.

That suggested surgery and radiation, which can cause side effects including scarring, chronic swelling, infection and nerve damage, would probably not improve outcomes for this group.

By contrast, patients whose ctDNA remained positive after receiving endocrine therapy were more likely to experience tumour growth while on the medication, suggesting surgery or other treatments may still be needed to achieve tumour control.

The study did not assess how well the treatments themselves worked. Instead, it focused on identifying an early decision window to help doctors judge which patients were less likely to respond to hormone therapy alone.

Priscilla F. McAuliffe, a breast surgical oncologist at UPMC Hillman and associate professor of surgery at the University of Pittsburgh’s School of Medicine, said: “We are learning that not every patient needs the same treatment based simply on their diagnosis, and instead, care should be right-sized for each individual.”

Because ctDNA can be measured through blood tests, patients were able to take part without frequent hospital visits.

Blood samples were often collected from patients’ homes, easing the burden of travel and allowing researchers to enrol patients from UPMC Hillman network oncology sites across the region, not just the main UPMC Hillman site in Shadyside.

The study also included feedback from patients and their caregivers.

When surveyed, more than 80 per cent of patients said ctDNA test results could help them feel better informed about treatment decisions, particularly during the first six to 12 months of care.

Caregivers said supporting loved ones often meant putting caregiving responsibilities ahead of work and other activities.

Based on the findings, the researchers said that, particularly for caregivers, having a monitoring option that can be carried out from home may be an important consideration.

For both patients and caregivers, they stressed the importance of careful patient education and shared decision-making throughout treatment.

The researchers cautioned that the study involved fewer than 50 patients and that the findings are not yet ready for standard practice.

Larger studies are needed before the approach could be used routinely.