Prognostic impact of circulating tumor DNA detection in portal and peripheral blood in resected pancreatic ductal adenocarcinoma patients

Abstract

In PDAC patients, ctDNA detection's prognostic significance needs validation especially in resected patients. This study investigated ctDNA kinetics in portal and peripheral blood before and after resection, and whether tissue mobilization during surgery influences ctDNA detection. In this single-center prospective cohort, portal and peripheral blood were drawn during pancreaticoduodenectomy before and after tissue mobilization, during 12 postoperative months and were associated with overall survival (OS), recurrence-free survival (RFS) and CA19-9 (secondary endpoints). Tumor mutations were identified using next-generation-sequencing and ctDNA detected by digital droplet PCR. From 2018 to 2022, 34 patients were included. The 2-year RFS and OS were 47.6%(95%CI[29.5; 63.6]) and 65.7%(95%CI[46.5; 79.4]) respectively. Intraoperatively, ctDNA detection in portal or peripheral blood was associated with worse RFS (HR[95%CI]3.26[1.26; 8.45],p = 0.010) and OS (HR[95%CI]5.46[1.65;18.01],p = 0.002). Portal vein sampling did not improve ctDNA detection. CtDNA levels were increased by 2.5-fold (p = 0.031) in peripheral blood after tissue mobilization but not significantly linked to RFS or OS. Detecting ctDNA intraoperatively was correlated with poorer RFS (HR [95% CI] 3.26 [1.26;8.45], p = 0.010) and 0S (HR [95% CI] 5.46 [1.65;18.01], p = 0.002). Portal vein sampling did not improve ctDNA detection. Tissue mobilization increases ctDNA levels. Intraoperative detection of ctDNA is associated with a worse prognosis.

Keywords: Circulating tumor DNA; Liquid biopsy; Overall survival; Pancreatic ductal adenocarcinoma; Recurrence-free survival; Tissue mobilization.

Fig. 1

Study flow chart. PDAC: Pancreatic Ductal Adenocarcinoma.

Fig. 2

Primary tumor mutations performed on the surgical specimen using next-generation-sequencing. KRAS mutations and codons are in red and other mutations are in black.

Fig. 3

Intraoperative data. Comparison of (A) peripheral and (B) portal cfDNA (copies/mL, mean, SD) and ctDNA (copies/mL, mean, SD) levels before and after tissue mobilization. (C) KRAS mutation detection in tumor specimen (“Tumor”) and in peripheral and/or portal vein, before and/or after tissue mobilization during surgery (“Peroperative ctDNA”). Recurrence-free survival (D) and Overall survival (E) according to evolution of ctDNA after mobilization comparing to before tissue mobilization. **** p < 0.0001, ** p < 0.01, * p < 0.05. ctDNA: Circulating tumor DNA, cfDNA: Circulating-Free DNA, NS: not significant, SD: Standard deviation.

Fig. 4

Postoperative data. (A) CtDNA detection and levels and recurrence. (B) Ca 19–9 levels and recurrence. (C) Examples of ctDNA detection and recurrence. BS: Before surgery, BEFORE-P: Peripheral blood before tissue mobilization, AFTER-P: Peripheral blood after tissue mobilization, BEFORE-PV: Portal blood before tissue mobilization, AFTER-PV: Portal blood after tissue mobilization, POD: Postoperative day, POM: Postoperative month. Arrows indicate clinical recurrence.