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Guardant Health has published results from what it describes as the largest study to date evaluating circulating tumor DNA for molecular residual disease in resected stage III colon cancer. The study was conducted with Mayo Clinic and the Alliance for Clinical Trials in Oncology, with findings reported in the Journal of Clinical Oncology.
The phase III study included more than 2,000 patients with stage III colon cancer following surgical resection. Using the Guardant Reveal blood test, approximately 20 percent of patients had detectable ctDNA after surgery. Those patients experienced a four- to six-fold higher risk of disease recurrence or reduced survival compared with patients without detectable ctDNA. The analysis also showed that ctDNA positivity identified elevated risk even among patients classified as lower risk by traditional TNM staging, including individuals with smaller tumors or fewer involved lymph nodes. In that subgroup, detectable ctDNA was associated with an event rate more than six times higher than in ctDNA-negative patients. Additional stratification by tumor fraction further differentiated patients at the highest risk of recurrence.
The findings reinforce the prognostic value of tissue-free ctDNA testing in the postoperative setting, showing that ctDNA status refines recurrence risk assessment beyond conventional TNM staging. Guardant's release states that ctDNA-based risk stratification could be used to guide adjuvant treatment and surveillance decisions, without stating changes to clinical guidelines or standards of care.
The publication aligns with themes discussed by Guardant co-CEO Helmy Eltoukhy during JPM Week 2025. In an Onyx interview, published in March 2025, Eltoukhy described the company’s focus across late-stage cancer testing, monitoring of cancer survivors, and early detection, and noted collaborations with approximately 180 biopharma companies. He also stated that Guardant recently received FDA approval, with Medicare coverage, for a blood-based test for early colorectal cancer detection, and expressed his belief that earlier detection technologies could reduce cancer mortality by more than 25 percent over the next decade.
You can read our previous interview with Helmy Eltoukhy here, and watch our video interview from JPM 2025 below:
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