Methods: Biopsy-proved advanced
pancreatic cancer patients who received systemic
chemotherapy were enrolled after signed informed consent. CA19-9 and
cfDNA in blood were measured before and after every two cycles of treatments, and the
disease progression was monitored by computed tomography (CT) with 3-month interval.
Results: In total, 74 patients and 148 blood samples were enrolled in this study. Patients whose average blood
cfDNA concentration of >9.71 ng/mL before and after first two courses of
chemotherapy would subsequently show new distant
metastasis (NDM) on CT scans 3 months later. The accuracy was 94.37% (AUC 0.9705, p < 0.0001) and the progression-free survival (PFS) and overall survival (OS) of patients with
cfDNA concentration of >9.71 ng/mL were worse than those patients with
cfDNA concentration of <9.71 ng/mL (median PFS: 95 days versus 322 days, p < 0.0001; median OS: 150 days versus 431 days, p < 0.0001). The
cfDNA concentration of >9.71 ng/mL is a predictor for PFS, OS, and distant
metastasis-free survival by multivariate analysis. Comparison of KRAS G12 variants detected by next-generation sequencing from
tumor tissue issue and remnant
DNA of
cfDNA showed that increased
cfDNA was primarily derived from
cancer cells.
Conclusion: