1. Circulating Tumor DNA Dynamics and Treatment Outcome of Regorafenib in Metastatic Colorectal Cancer.
- Author
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Lee DW, Lim Y, Kim HP, Kim SY, Roh H, Kang JK, Lee KH, Kim MJ, Ryoo SB, Park JW, Jeong SY, Park KJ, Kang GH, Han SW, and Kim TY
- Subjects
- Humans, Protein-Tyrosine Kinases genetics, Proto-Oncogene Proteins genetics, Treatment Outcome, Biomarkers, Tumor genetics, Mutation, Circulating Tumor DNA genetics, Colonic Neoplasms pathology, Cell-Free Nucleic Acids, Rectal Neoplasms, Colorectal Neoplasms drug therapy, Colorectal Neoplasms genetics
- Abstract
Purpose: Circulating tumor DNA (ctDNA) is emerging as a valuable non-invasive tool to identify tumor heterogeneity and tumor burden. This study investigated ctDNA dynamics in metastatic colorectal cancer patients treated with regorafenib., Materials and Methods: In this prospective biomarker study, plasma cell-free DNA (cfDNA) samples obtained at baseline, at the first response evaluation after 2 cycles of treatment, and at the time of progressive disease were sequenced using a targeted next-generation sequencing platform which included 106 genes., Results: A total of 285 blood samples from 110 patients were analyzed. Higher baseline cfDNA concentration was associated with worse progression-free survival (PFS) and overall survival (OS). After 2 cycles of treatment, variant allele frequency (VAF) in the majority of ctDNA mutations decreased with a mean relative change of -31.6%. Decreases in the VAF of TP53, APC, TCF7L2, and ROS1 after 2 cycles of regorafenib were associated with longer PFS. We used the sum of VAF at each time point as a surrogate for the overall ctDNA burden. A reduction in sum (VAF) of ≥ 50% after 2 cycles was associated with longer PFS (6.1 vs. 2.7 months, p=0.002), OS (11.3 vs. 5.9 months, p=0.001), and higher disease control rate (86.3% vs. 51.1%, p < 0.001). VAF of the majority of the ctDNA mutations increased at the time of disease progression, and VAF of BRAF increased markedly., Conclusion: Reduction in ctDNA burden as estimated by sum (VAF) could be used to predict treatment outcome of regorafenib.
- Published
- 2023
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