手術治療膵管腺癌における予後予測ツールとしての循環腫瘍DNA
Trine Aaquist1, Tenna Vesterman Henriksen2, Lea Lecanda Mariager Jakobsen3
1Department of Pathology, Odense University Hospital, Odense, Denmark; Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; OPEN - Open Patient data Explorative Network, Odense University Hospital, Region of Southern Denmark.
Introduction:
Pancreatic ductal adenocarcinoma (PDAC) has a high risk of early recurrence after surgery. We evaluated the utility of circulating tumour DNA (ctDNA) taken at different time points as a prognostic tool. Secondary aims were prognostic value of ctDNA combined with plasma carbohydrate antigen (CA)-19-9 and of peritoneal tumour DNA (ptDNA).
Methods:
A total of 75 patients were included. Plasma samples were obtained preoperatively, 1 month, and 7-9 months after resection. Peritoneal lavage fluid (PLF) was collected preoperatively and 7-9 months after resection. Cell-free DNA (cfDNA) from plasma and ptDNA was analysed using mutation specific digital droplet PCR assays in a tumour-informed apprach. Kaplan-Meier survival curves, univariable, and multivariable Cox proportional hazard models were used to assess overall survival (OS) and recurrence-free survival (RFS).
Results:
Preoperatively, detectable ctDNA was an independent risk factor for OS (HR=1.88, p=0.047). Detectable ctDNA 7-9 months after surgerywas an independent risk factor for RFS (HR=4.48, p=0.017). Detectable ctDNA 1 month after surgery showed decreased RFS (HR=1.98, p=0.055). Preoperative, 1-month, and 7-9 months postoperative positivity for ctDNA and/or CA 19-9 showed a significantly worse median OS (p=0.024, p=0.008, and p=0.0003). We did not find association of ptDNA with OS or RFS, but ptDNA detection 7-9 months after surgery was associated with peritoneal RFS (p=0.003).
Conclusion:
Our data indicate that detectable ctDNA in plasma taken before and 7-9 months after surgery holds independent prognostic value in surgically treated PDAC. Combination of ctDNA with CA-19-9 may be a particularly strong prognosticator, which should be confirmed in future studies.
