A Tumor-Naïve ctDNA Assay Detects Minimal Residual Disease in Resected Stage II or III Colorectal Cancer and Predicts Recurrence: Subset Analysis from the GALAXY Study in CIRCULATE-Japan.
Nakamura Y., Kaneva K., Lo C., Neems D., Freaney JE., Boulos H., Hyun SW., Islam F., Yamada-Hanff J., Driessen TM., Sonnenschein A., DeSantis DF., Kotani D., Watanabe J., Kotaka M., Mishima S., Bando H., Yamazaki K., Taniguchi H., Takemasa I., Kato T., Sangli C., Tell R., Blidner R., Yoshino T., Sasser K., Oki E., Nimeiri H.
PURPOSE: Analysis of ctDNA may enable early identification of patients likely to relapse, presenting an opportunity for early interventions and improved outcomes. Tumor-naïve plasma-only approaches for minimal residual disease (MRD) assessment accelerate turnaround time, enabling rapid treatment decisions and ongoing surveillance. EXPERIMENTAL DESIGN: Plasma samples were obtained from 80 study participants with stage II or III colorectal cancer selected from CIRCULATE-Japan GALAXY. MRD status was assessed using a tumor-naïve ctDNA assay (xM) that integrates methylation and genomic variant data, delivering a binary call. MRD was assessed at 4 weeks postsurgery [landmark time point (LMT)] using methylation and genomic variant data and longitudinally (median, 22.1 months) using only methylation data. RESULTS: At LMT, 69/80 study participants were evaluable (36 recurrent; 33 nonrecurrent). Of recurrent study participants, 22/36 had detectable ctDNA (MRD-positive) at LMT and 29/33 nonrecurrent study participants had undetectable ctDNA (MRD-negative), yielding a clinical sensitivity of 61.1% and specificity of 87.9%. Additionally, 74 study participants were evaluable for longitudinal performance with a clinical sensitivity of 83.3% and specificity of 89.5%. The median lead time from the first MRD-positive result to recurrence was 4.77 months overall, and 5.30 months for study participants with no adjuvant treatment. At 12 weeks postsurgery, MRD status strongly correlated with disease-free survival (adjusted HR, 9.69), outperforming carcinoembryonic antigen correlation (HR, 2.13). CONCLUSIONS: This tumor-naïve MRD assay demonstrated clinically meaningful performance at LMT and longitudinally, accurately predicting clinical recurrence. MRD status was a stronger prognostic biomarker for disease-free survival compared with standard-of-care carcinoembryonic antigen.