Ultrasensitive ctDNA Assay Detects MRD in Breast, Colorectal, Renal Cancers
Posted on 26 Jun 2026
Minimal residual disease testing is increasingly used to guide adjuvant therapy and surveillance in solid tumors, but detecting very low levels of circulating tumor DNA remains challenging in routine practice. With breast, colorectal, and renal cancers affecting large U.S. patient populations, demand is growing for ultrasensitive approaches that can be deployed across care settings. A newly expanded assay broadens access for these tumor types while providing longitudinal, quantitative insight into disease status.
Myriad Genetics (Salt Lake City, UT, USA) has expanded availability of Precise MRD to patients undergoing treatment and surveillance for breast, colorectal, and renal cancers. The company notes that more than 6 million individuals are living with these cancers in the U.S., representing a substantial increase in access. The expansion is presented alongside new peer‑reviewed evidence supporting use of the assay in breast cancer.
Precise MRD is a next‑generation, whole‑genome sequencing–based assay that builds a patient‑specific panel by tracking up to 1,000 tumor‑informed variants. By quantifying circulating tumor DNA (ctDNA), the test provides a dynamic, quantitative view of disease status from neoadjuvant therapy through post‑surgical assessment and long‑term surveillance. Its ultrasensitive design is described as enabling robust detection of ctDNA even in low‑shedding tumors, with consistent performance across varied clinical contexts.
Results from the prospective, multi‑center MONITOR‑Breast study, published in Future Oncology, further support the clinical validity of Precise MRD in breast cancer. In the study of 154 patients with Stage I–III disease across molecular subtypes, investigators analyzed 949 plasma samples collected longitudinally during neoadjuvant therapy and subsequent care. Ultrasensitive ctDNA monitoring provided real‑time insight into treatment response and helped identify patients at increased risk for residual disease.
Key findings included baseline ctDNA detection in 93% of patients, including 20% detected at levels below 100 parts per million. The assay predicted pathological complete response with 100% specificity. Patients who were ctDNA‑positive at the end of neoadjuvant therapy were 47 times more likely to remain ctDNA‑positive after surgery, and longitudinal testing identified 44% more patients at risk for residual disease than a single post‑therapy timepoint. Sustained ctDNA clearance occurred in 78% of patients and was associated with higher rates of pathological complete response, while 22% showed persistent or intermittent positivity.
Precise MRD is positioned for integration across academic and community oncology workflows at key decision points, including neoadjuvant monitoring, post‑surgical assessment, and surveillance.
“Expanding Precise MRD into breast, colorectal and renal cancers marks a significant step forward in our broader precision oncology strategy,” said Brian Donnelly, Chief Commercial Officer, Myriad Genetics. “In a single, easy-to-read report, Precise MRD delivers ultrasensitive ctDNA detection and longitudinal insights, along with the clinical interpretation support clinicians need to help guide treatment and surveillance decisions. As we continue to expand across tumor types and build clinical evidence, we believe Precise MRD will play an increasingly central role in managing cancer care.”
“MONITOR-Breast highlights the strength of a whole-genome, tumor-informed approach to MRD detection,” said Dale Muzzey, Chief Scientific Officer, Myriad Genetics. “Precise MRD enables ultrasensitive ctDNA detection and longitudinal disease monitoring that captures dynamic treatment response. The ability to identify additional at-risk patients through frequent sampling, beyond a single timepoint assessment, demonstrates the importance of molecular monitoring in improving risk stratification and guiding clinical decision-making.”
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