Blood Test Helps Guide Treatment in Older Women with Breast Cancer

Clinicians have had limited tools to individualize therapy for patients age 70 and over who may opt for endocrine therapy alone. Minimizing overtreatment while maintaining tumor control remains a key challenge. Researchers now report that a blood-based circulating tumor DNA test may help guide these decisions.

Scientists at the University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center evaluated a blood-based circulating tumor DNA (ctDNA) test for women age 70 and above with estrogen receptor–positive disease who were considering endocrine (hormone-blocking) therapy as the primary treatment and forgoing surgery and radiation. The approach analyzes small fragments of tumor-derived DNA in plasma and interprets their presence or absence to stratify likelihood of response. The objective was to define an early decision window to identify patients less likely to benefit from endocrine therapy alone.

The study, published March 19 in Clinical Cancer Research, did not assess treatment efficacy directly but examined whether ctDNA status could inform management. Patients who were ctDNA-negative at baseline or after initiating endocrine therapy were more likely to have stable disease or tumor shrinkage, suggesting that additional local therapies would be unlikely to improve outcomes in this group. In contrast, patients with persistently positive ctDNA after starting therapy were more likely to experience tumor growth while on medication, indicating that surgery or other treatments may be needed to achieve tumor control.

Because ctDNA can be measured through blood sampling, many specimens were collected at patients’ homes, reducing travel and enabling participation across the UPMC Hillman Cancer Center network, including UPMC Passavant–Cranberry, UPMC Jameson and UPMC St. Margaret. More than 80% of patients reported that ctDNA results could help them feel more informed about treatment choices during the first six to 12 months, and caregivers described the need to balance supportive roles with other responsibilities. Investigators emphasized that this was a small study of fewer than 50 patients and that larger studies are needed before these findings can be applied in standard practice.

“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 Priscilla F. McAuliffe, associate professor of surgery, University of Pittsburgh School of Medicine, and breast surgical oncologist at UPMC Hillman Cancer Center.

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

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University of Pittsburgh School of Medicine 
UPMC Hillman Cancer Center