Highlight
1. Change in circulating tumor DNA (ctDNA) at 1-month post-treatment initiation predicts progression-free survival (PFS) and overall survival (OS) in dMMR/MSI-H metastatic colorectal cancer (mCRC) treated with immune checkpoint inhibitors (ICIs).
2. Baseline ctDNA positivity or concentration alone does not correlate with patient outcomes.
3. Patients treated with avelumab who exhibit favorable early ctDNA response have significantly improved survival compared to chemotherapy-treated patients.
4. Combined early ctDNA response and RECIST assessment accurately predict long-term survival, potentially guiding personalized treatment strategies.
