Dr. Gorawich Kerkarchachai presented the case of a 56-year-old patient with post-surgery stage II (pT3N0M0) sigmoid colon cancer with high-risk features. While conventional molecular profiling was negative and indicated microsatellite stability (MSS), tumor-informed ctDNA detected minimal residual disease (MRD) positivity driven by a TP53 mutation.
Given data from the DYNAMIC trial demonstrating that the addition of oxaliplatin numerically increased the rate of ctDNA clearance, a thorough discussion was held with the patient. It was emphasized that achieving ctDNA clearance (converting from positive to negative) is strongly correlated with substantially improved survival outcomes. Consequently, a shared decision was reached to escalate the treatment from single-agent capecitabine to the CAPEOX regimen. After four cycles, the ctDNA successfully converted to negative and remained undetectable during subsequent follow-up. This case demonstrates how ctDNA can refine risk stratification beyond traditional pathology and effectively guide personalized treatment decisions.
<iframe width="560" height="315" src="https://www.youtube.com/embed/32eZz7NgcuI" title="Colon case spotlight: ctDNA‑guided escalation in early‑stage cancer" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
