Analysis of the clinical value of postoperative circulating tumor DNA (ctDNA) within the first month for resected colorectal cancer in a real-world.

Purpose: Analysis of the clinical value of postoperative circulating tumor DNA (ctDNA) within the first month for resected colorectal cancer in a real-world. Methods In this longitudinal cohort study, 42 resectable CRC patients with stage I-III were enrolled and treated per standard of care. Tumor tissues (n = 42) and serial plasma samples (n = 161) were collected and detected with massively parallel sequencing to evaluate somatic variants. Recurrence monitoring during approximately 2 years of follow-up period was performed. Survival analysis was performed by the Kaplan-Meier method, based on the Log-Rank test. Results Mutation profiling in paired baseline tissues and plasma samples demonstrated a good concordance (P<0.01). Serial analysis of ctDNA profiling indicated mutation status of CRC-related driver genes and DNA damage repair pathway genes in this cohort were tightly correlated with clinical recurrence. Longitudinal ctDNA detection revealed ctDNA positivity was closely associated with an inferior recurrence-free survival in the whole course of pre- or postoperation, especially ctDNA status in first month postoperatively (P = 0.037). Furthermore, ctDNA status in first month post-operation was the strongest independent risk factor for predicting recurrence after adjusting for clinicopathologic indexes in the multivariate analysis (HR = 24; 95% CI, 2.168–265.8; P = 0.01). Combination of postoperative ctDNA status in 1 month with clinical risk stratification based on clinicopathologic characteristics also significantly improved classification of prognosis (P = 0.008). CtDNA predicted recurrence with an average lead time of 5 months compared with CT imaging. Conclusion CtDNA within the first month is great importance to hint prognosis and predict response to adjuvant therapy.