by Anne Vetter, Nationales Centrum für Tumorerkrankungen (NCT/UCC) Dresden

Credit: Michael Kretzschmar, UKD

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 clinical study led by Dresden University Hospital now provides important insights for a robust basis for decision-making.

These findings were presented at the annual meeting of the American Society of Clinical Oncology (ASCO) andpublished simultaneously in theAnnals 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 publishedCIRCULATE studyis 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 strongprognostic value of ctDNA: Three years after surgery, 87% of ctDNA-negative patients remained free of recurrence, compared with only 52% 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% with chemotherapy, compared with 38% 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.

"TheCIRCULATE studyis 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 said.

Publication details G. Folprecht et al, Chemotherapy for patients with circulating tumour DNA positive, stage II colon cancer (CIRCULATE) – an AIO / ABCSG trial, Annals of Oncology (2026). DOI: 10.1016/j.annonc.2026.05.001 Journal information: Annals of Oncology