Circulating Tumor DNA Methylation Is a Biomarker of Poor Recurrence-free Survival in Locally-Advanced Rectal Cancer.

BACKGROUND/AIM: The aim of this study was to investigate locus-specific circulating-tumor DNA (ctDNA) methylation for predicting long-term outcomes of locally-advanced rectal cancer (LARC) after resection.

MATERIALS AND METHODS

In the present study, there were 50 patients without preoperative treatment and 35 patients with preoperative treatment. Methylation analyses for checkpoint with forkhead and ring finger domains (), sex-determining region Y-box transcription factor 11 () and cysteine dioxygenase type 1 () used DNA extracted from plasma ctDNA at the time of resection of the primary tumor with curative-intent surgery.

RESULTS

Highly-methylated in ctDNA was found to be a biomarker of reduced recurrence-free survival (RFS) in LARC. In multivariate analysis, highly methylated was an independent prognostic factor for reduced RFS in the group without preoperative treatment.

CONCLUSION

The present study demonstrates that elevated ctDNA methylation of the gene is a biomarker for reduced RFS after curative-intent resection of LARC. Patients with high ctDNA methylation of the gene may not be optimal candidates for LARC resection. A prospective study is necessary to further validate ctDNA methylation as a biomarker for RFS of patients with LARC.