News|Articles|April 1, 2026

Blood Test May Help Older Patients With Breast Cancer Safely Avoid Surgery

Fact checked by: Alex Biese

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Key Takeaways

Prospective follow-up of 43 women ≥70 years with stage I–III ER+/HER2− disease managed with primary endocrine therapy incorporated Signatera ctDNA testing at baseline and every 3–6 months.
Baseline MRD negativity occurred in 68% (23/34) and was associated with zero observed progression, supporting strong negative predictive value for safely deferring surgery.
Among MRD-positive patients, 64% (7/11) cleared ctDNA by 6 months on endocrine therapy and all remained free of distant progression.
ctDNA monitoring detected all five growth/recurrence events ahead of imaging, and >80% reported improved informational confidence without increased anxiety, suggesting feasibility for geriatric de-escalation pathways.

A new study shows Signatera ctDNA testing may identify older patients with ER+/HER2- breast cancer who can manage their care without invasive surgery.

Older patients with early-stage breast cancer may have a reliable new way to skip surgery while still safely managing their health, according to a study recently published in Clinical Cancer Research. The research, conducted by Natera, Inc. and the University of Pittsburgh, found that a specialized blood test called Signatera can accurately monitor patients who choose primary endocrine therapy instead of a surgical procedure, according to a news release from Natera, Inc.

By tracking circulating tumor DNA (ctDNA) in the bloodstream, the study showed that doctors can identify which patients are responding well to medication and catch signs of disease progression earlier than traditional imaging. This approach offers a personalized way for patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer to make treatment decisions that prioritize their quality of life.

Main data that support the findings

The study results highlighted how molecular residual disease (MRD) testing, which looks for tiny traces of cancer left in the body, can predict patient outcomes. At the beginning of the study, 68% of patients (23 out of 34) tested MRD-negative. Not one of these patients saw their cancer progress during the study, showing that the test is highly accurate at identifying those at low risk for the disease returning or worsening.

For the 11 patients who initially tested MRD-positive, researchers tracked how their cancer reacted to hormone therapy over time. Key findings included:

Treatment response: 64% of the MRD-positive group (seven out of 11 patients) saw their blood clear of tumor DNA after six months of medication.
Preventing spread: All seven of those patients remained free of distant progression, which is when cancer spreads to other organs.
Early warning: One patient experienced a local return of cancer, but the blood test detected it before it could be seen on a standard scan.
Sensitivity: In total, five patients had their tumors grow or return, and the blood test flagged all five cases before imaging did.

Beyond the clinical numbers, the study looked at how the test affected the people using it. More than 80% of participants said the test results helped them feel more informed about their care, and they did not report an increase in anxiety after receiving the information.

Trial details

This prospective study followed 43 women, all aged 70 or older, who were diagnosed with stage 1, 2 or 3 ER+/HER2- breast cancer. Because of their age or personal preferences, every woman in this group chose to forgo surgery and instead manage the cancer using primary endocrine therapy.

The monitoring process was designed to be consistent and thorough:

Baseline: Each patient received an initial Signatera test before starting treatment.
Ongoing Checks: Patients were tested every three to six months.
Comparison: These blood tests were used alongside standard physician visits and regular imaging, such as mammograms or ultrasounds, to ensure the test was providing accurate and timely information.

Safety

The study explored how this technology could safely support non-surgical treatment plans for older patients. Dr. Priscilla F. McAuliffe, a surgical oncologist at the University of Pittsburgh and lead author of the study, explained in the news release that care for older patients often requires a balance between managing the cancer and considering a person’s overall health and preferences.

The data suggests that by using ctDNA monitoring, doctors can better identify which patients can safely skip surgery. Because the test provides an early signal if the cancer starts to grow, it allows for a more proactive approach to care. Dr. Angel Rodriguez, senior medical director of oncology at Natera, noted in the news release that this tool helps physicians monitor how well the treatment is working in real time, providing an extra layer of safety and confidence for patients who prefer to avoid invasive procedures.

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI, reviewed by a human editor, but not independently verified by a medical professional.