Liquid Biopsy Shows Promise in Guiding Chemotherapy Decisions for Stage III Colon Cancer
Table of Contents
A new study presented at the European Society for Medical Oncology (ESMO) 2025 meeting suggests that a liquid biopsy test could help doctors determine which patients with stage III colon cancer would benefit most from chemotherapy following surgery, potentially reducing unnecessary treatment and its associated side effects. The research, unveiled on Sunday, October 19, 2025, at 23:05 UK time, offers a glimpse into a future of more personalized cancer care.
The Challenge of Overtreatment in Colon Cancer
Currently, many patients with stage III colon cancer receive adjuvant chemotherapy – treatment given after surgery – to reduce the risk of the cancer returning. However, experts estimate that up to 50% of these patients may already be cured by surgery alone, meaning they are subjected to chemotherapy without any added benefit. This overtreatment exposes them to potentially debilitating side effects.
“A major problem in clinical practice is that we overtreat many patients,” explained a leading medical oncologist. “Until recently, we had no tests to identify those patients who don’t need chemotherapy.”
DYNAMIC-III Trial: A Step Towards Precision
The Phase 3 DYNAMIC-III trial investigated whether a highly sensitive circulating tumor DNA (ctDNA) test could identify patients who could safely avoid or reduce chemotherapy. The trial utilized a state-of-the-art test capable of detecting even minute amounts of DNA shed from any remaining cancer cells, known as micrometastases.
The initial results of the trial were described as “formally negative,” meaning the study did not achieve its primary endpoint of demonstrating a statistically significant difference in recurrence rates between the groups. However, a closer look at the data revealed a promising trend. While the overall recurrence rate was slightly higher in the group where ctDNA guided chemotherapy decisions, a subgroup analysis focusing on patients with low-risk stage III tumors – those with up to three positive lymph nodes – showed that reducing or omitting chemotherapy was potentially non-inferior to standard treatment.
Liquid Biopsy: Not a One-Size-Fits-All Solution
Despite the encouraging findings, researchers caution that ctDNA testing alone is not yet sufficient to determine who can safely skip chemotherapy. “This shows that the circulating tumor DNA test alone is insufficient to determine in which patients chemotherapy can be omitted without risking under-treatment,” one expert stated.
Further research is needed to refine the use of ctDNA and to determine how it can be combined with other risk factors to create a more comprehensive and accurate prediction of recurrence. .
The Future of Personalized Chemotherapy
Experts believe that liquid biopsy technology holds significant promise for tailoring chemotherapy regimens to individual patients. A senior clinical fellow noted that the study adds evidence supporting the idea that doctors will eventually be able to better select patients for chemotherapy, ensuring that only those who truly need it receive the treatment.
“It may well be that the test they used was not sensitive enough to pick the right patients for chemotherapy,” the fellow added, emphasizing the rapid advancements in liquid biopsy technology. “Liquid biopsy technology is developing very fast, and this study relies on follow-up data that has taken several years to generate.”
The abstract, ‘ctDNA-guided adjuvant chemotherapy de-escalation in stage III colon cancer: Primary analysis of the ctDNA-negative cohort from the randomized AGITG DYNAMIC-III trial (Intergroup study of AGITG and CCTG)’ by P. Gibbs et al., represents a crucial step toward minimizing unnecessary treatment and improving the quality of life for patients battling colon cancer. While more research is necessary, the findings offer a hopeful outlook for a future where cancer treatment is more precise, personalized, and effective.
Disclosure
A senior clinical fellow disclosed a financial interest, stating they are a co-inventor and patent holder for a liquid biopsy assay and receive research funding from Oxford Nanopore and Natera. No disclosures were received from other experts involved in the research.
