A blood test may better tailor breast cancer treatment for older women, reveals study

For women age 70 and over with a common form of breast cancer, determining “the right size” of treatment can be challenging, in part because clinicians have limited tools to guide individualized treatment decisions.

In a study published today in Clinical Cancer Research, scientists at UPMC Hillman Cancer Center and the University of Pittsburgh School of Medicine found that a blood-based test may help guide treatment decisions for a carefully selected group of women age 70 and over who have estrogen receptor–positive breast cancer, who were considering endocrine (or hormone-blocking) therapy as the primary treatment and forgoing surgery and radiation.

“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,” said senior author Priscilla F. McAuliffe, M.D., Ph.D., a breast surgical oncologist at UPMC Hillman and associate professor of surgery at Pitt’s School of Medicine.

Researchers analyzed blood samples for circulating tumor DNA (ctDNA), small fragments of genetic material shed by cancer cells. They assessed whether the presence or absence of these fragments could identify patients who were unlikely to respond to endocrine therapy alone.

Patients whose ctDNA test was negative, either at the start of the treatment or after beginning endocrine therapy, were more likely to have stable disease or tumor shrinkage. This meant surgery and radiation - both of which can result in side effects, including scarring, chronic swelling, infection and nerve damage – probably wouldn’t improve outcomes for this group of patients.

In contrast, patients whose ctDNA remained positive after receiving endocrine therapy were more likely to experience tumor growth while receiving the medication, suggesting that surgery or other treatments may still be necessary to achieve tumor control in this group.

The study did not evaluate the effectiveness of the treatments. Instead, it focused on identifying an early decision window that can help doctors determine which patients are less likely to respond to hormone therapy alone.

Because ctDNA can be measured through blood tests, patients were able to participate without frequent trips to the hospital. Blood samples were often collected from patients’ homes, reducing the burden of travel and allowing researchers to enroll patients from UPMC Hillman network oncology sites across the region, not just at the main UPMC Hillman in Shadyside.

“We worked really hard to include patients outside the main academic center, including UPMC Passavant Cranberry, UPMC Jameson and UPMC St. Margaret,” said lead author, Neil Carleton, M.D., Ph.D., a post-doctoral fellow at Pitt. “Making care more convenient for patients, including access to clinical trials, is a priority at UPMC Hillman Cancer Center.”

The study also included feedback from both patients and their caregivers, a group often not included in clinical trials. When surveyed, more than 80% of patients reported that ctDNA test results could help them feel more informed about their treatment decisions, particularly during the first six to 12 months of care. Caregivers reported that supporting their loved ones in their breast cancer treatment often required prioritizing caregiving responsibilities over work and other activities.

Based on these findings, the researchers suggest that, particularly for caregivers, having a monitoring option that can be conducted from home may be an important consideration. For both patients and caregivers, the researchers emphasized the importance of careful patient education and shared decision-making throughout the treatment process.

Researchers caution that this was a small study involving fewer than 50 patients, and that the findings are not yet applicable to standard practices. Larger studies are needed before this approach could be used routinely.

Reference:

Neil Carleton, Alexander C. Chang, Fangyuan Chen, Shannon L. Puhalla, Use of ctDNA in Older Women with ER+ Breast Cancer to Facilitate Surgical De-escalation: A Prospective, Hybrid-Decentralized Trial with Correlative Studies, Clinical Cancer Research, https://doi.org/10.1158/1078-0432.CCR-25-4079