Circulating Tumor DNA Testing: A Proactive Approach to Detecting Breast Cancer Recurrence
For many who have completed treatment for invasive breast cancer, one of the hardest parts of recovery is the uncertainty that follows. The standard approach to surveillance has traditionally relied on imaging and physical symptoms — meaning a recurrence often isn’t caught until it has already progressed. That reality is changing, thanks to circulating tumor DNA (ctDNA) testing.
What Is Circulating Tumor DNA?
Circulating tumor DNA refers to small fragments of DNA shed by cancer cells into the bloodstream. These fragments carry the unique genetic signature of a tumor, making them a highly specific marker for detecting cancer — even in amounts too small to appear on imaging. Because ctDNA testing requires only a blood draw rather than a tissue biopsy, it’s sometimes called a “liquid biopsy” — and it’s shifting cancer monitoring from reactive to proactive.
How Signatera Works
One of the leading ctDNA tests available today is Signatera, developed by Natera. What makes Signatera unique is that it’s custom-built for each patient.
After surgery, a sample of the original tumor tissue is analyzed to map its unique genetic mutations. Natera then builds a personalized test — essentially an “avatar” of the tumor — calibrated to detect those exact mutations in the bloodstream. Once built, monitoring is simple: a routine blood draw is all that’s needed each time. The test tracks whether tumor DNA fragments are present, rising, falling, or absent — offering a real-time molecular window into what’s happening in the body.
Studies have shown Signatera can detect recurrence a median of 10.5 months before imaging would, with 88% sensitivity and a positive predictive value over 98%
Why Early Detection Changes Everything
When recurrence is caught at the molecular level — before it shows up on a scan or causes symptoms — treatment options are broader and intervention can begin sooner. Rather than waiting and watching, ctDNA testing gives both patients and care teams a measurable, actionable tool for staying ahead of the disease.
The process itself is straightforward. After the initial personalized test is designed from the tumor sample, each follow-up requires nothing more than a standard blood draw. Results can show whether cancer may be returning, responding to treatment, or in remission — empowering more informed decisions at every stage of survivorship.
Who Can Benefit?
While ctDNA testing has gained significant traction in breast cancer care, it isn’t limited to breast cancer alone. Signatera is also used for colorectal cancer, bladder cancer, non-small cell lung cancer, and ovarian cancer, among others. For breast cancer specifically, Signatera has Medicare coverage for stage IIb and higher in adjuvant and surveillance settings, as well as stage II–IV in the neoadjuvant setting.
That said, ctDNA monitoring isn’t appropriate for every patient or every situation. The decision is a personal one, best made in partnership with your oncology team based on your diagnosis, treatment history, and risk factors. If you have a history of invasive breast cancer, it’s worth asking your medical oncologist whether this type of proactive monitoring might be right for you.
“Imagine going through cancer treatment only to find out the only way you’ll know if it’s come back is for symptoms to show up. Wonderfully, that’s not the reality anymore.” – Dr. Anne Peled
Moving Forward with Confidence
Cancer recurrence monitoring has evolved. Tools like Signatera are giving patients and their care teams the ability to move beyond waiting and into a more proactive approach — one that prioritizes early detection, informed decision-making, and peace of mind. If you’re interested in learning more, start the conversation with your medical oncologist. Taking that step is one of the most empowering things you can do for your long-term health.
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