Blood test improves treatment decisions for colon cancer: Dresden study on circulating tumor DNA shows clear benefits

After surgery for colon cancer, many patients face the question of whether follow-up chemotherapy is necessary to prevent a possible relapse. The decision is particularly difficult in so-called Stage II, the intermediate-risk group: Although around one in five untreated patients suffers a relapse, adjuvant chemotherapy places a significant and, in some cases, unnecessary burden on many patients. A large clinical study led by Dresden University Hospital now provides important insights for a robust basis for decision-making. These findings were presented for the first time at this year’s annual meeting of the American Society of Clinical Oncology (ASCO) and published simultaneously in the Annals of Oncology.

Tumors release tiny fragments of their DNA into the bloodstream. This so-called circulating tumor DNA (ctDNA) can be detected in the blood using modern molecular biological methods. The recently published CIRCULATE study is the first randomized trial to specifically investigate whether patients with detectable ctDNA benefit from chemotherapy.

Between 2020 and 2025, more than 2,100 patients in Germany and Austria were enrolled in the study. Patients with a positive ctDNA result were randomly assigned either to receive chemotherapy or to undergo the current standard treatment, namely observation only.

The results first confirmed the strong prognostic value of ctDNA: Three years after surgery, 87 percent of ctDNA-negative patients remained free of recurrence, compared with only 52 percent in the ctDNA-positive group.

Furthermore, the study demonstrated a concrete therapeutic effect for the first time in a randomized trial: Among the patients who actually received treatment, the three-year relapse-free survival rate was 77 percent with chemotherapy, compared with 38 percent without treatment. The risk of recurrence was therefore significantly reduced.

“This study provides two key findings,” explained study leader Prof. Gunnar Folprecht, an oncologist and senior physician at Medical Clinic I of Dresden University Hospital (UKD). “We were able to confirm that ctDNA is a clinically significant risk marker. More importantly, we demonstrated that patients who test positive for ctDNA actually benefit from chemotherapy.”

For clinical practice, this could mean that patients without detectable ctDNA can forgo chemotherapy, while those who test positive for ctDNA should receive more targeted treatment.

“A prerequisite for curing colon cancer is excellent surgery. To ensure long-term treatment success in patients with colon cancer, chemotherapy tailored to the individual risk of relapse after surgery is also significant,” emphasized Prof. Jürgen Weitz, co-author of the study, Director of the Department of Visceral, Thoracic and Vascular Surgery at the University Hospital Dresden, and one of the Managing Directors of the National Center for Tumor Diseases Dresden.

“The CIRCULATE study is an impressive example of how translational research transforms molecular insights into clinically useful evidence. Academic clinical trials are a central focus of Dresden University Medicine. CIRCULATE demonstrates the potential that translational oncology holds for the patient care of tomorrow,” said Prof. Esther Troost, Dean of the Faculty of Medicine at TU Dresden.

“For our patients, these results represent a real opportunity,” said Prof. Uwe Platzbecker, Medical Director of the University Hospital Dresden (UKD). “At UKD, we have the prerequisites to bring such innovative approaches into clinical practice through clinical trials once the framework conditions are clarified.”

However, there are still obstacles to the widespread use of this treatment approach. The test used in the study is not yet commercially available. Although commercial alternatives do exist, the costs are currently not routinely covered by statutory health insurance providers in Germany. “Before ctDNA-based treatment decisions can become part of everyday clinical practice, issues regarding availability and financing need to be resolved,” Folprecht summarized.

About the study:
The CIRCULATE study was designed at Dresden University Hospital and funded by the Federal Ministry of Research, Technology and Space (BMFTR). Participants included the German Society for Medical Oncology (AIO), the Austrian Breast & Colorectal Cancer Study Group (ABCSG), Ruhr University Bochum, and more than 140 study centers in Germany and Austria.

Publication: “CIRCULATE — Chemotherapy for patients with circulating tumor DNA positive, stage II colon cancer”, DOI: 10.1016/j.annonc.2026.05.001: https://www.sciencedirect.com/science/article/pii/S0923753426001808?via%3Dihub
Principal investigator: Prof. Gunnar Folprecht, Carl Gustav Carus University Hospital, TU Dresden

Background:
The CIRCULATE study is part of a rapidly evolving field of research. Together with findings from international studies — including the DYNAMIC study in Australia and the GALAXY study in Japan — the evidence is mounting that ctDNA testing could accurately personalize treatment planning for colon cancer in the future. The ongoing French CIRCULATE-PRODIGE-70 study is expected to provide additional data.

Academic contacts:
Prof. Gunnar Folprecht
Medical Clinic I
Carl Gustav Carus University Hospital, TU Dresden
gunnar.folprecht@ukdd.de

Media contact:
Anne-Stephanie Vetter
Staff Unit Public Relations of the Carl Gustav Carus Faculty of Medicine of TUD Dresden University of Technology
National Center for Tumor Diseases (NCT/UCC) Dresden
Tel.: +49 351 458 17903
anne-stephanie.vetter@tu-dresden.de