ctDNA and Minimal Residual Disease in Curative-Intent Colorectal Cancer

Key points addressed in this conversation include:

• Stage 2 and 3 disease: ctDNA is most validated in resected stage 2 and 3 CRC, where it may help identify patients who could safely forgo adjuvant chemotherapy, particularly in low-risk stage 2 cases. The panel notes that discordance between ctDNA results and traditional clinicopathologic risk factors warrants careful consideration.
• Dynamic testing: Sequential ctDNA assessments can increase confidence in detecting residual disease and may influence decisions about adjuvant therapy timing and intensity.
• Trial interpretations: The panel reviews findings from trials like DYNAMIC and GALAXY, acknowledging variability in assays, endpoints, and intervention strategies, which complicates interpretation and application in practice.
• Challenges and optimism: Although MRD-positive patients often relapse despite current therapies, ongoing research into targeted and immune-based strategies offers hope for interventions that could truly alter outcomes. The discussion underscores that ctDNA’s utility is intertwined with drug availability, patient selection, and timing, and that continued studies are critical to define its role in routine care.

Overall, this segment provides an in-depth exploration of how ctDNA and MRD testing are reshaping surveillance and treatment decisions in curative-intent CRC, balancing optimism for the future with practical considerations for implementation today.