Analysis of Cell-Free DNA to Assess Risk of Tumoremia Following Endoscopic Ultrasound Fine-Needle Aspiration of Pancreatic Adenocarcinomas

Abstract

In patients with PDAC, EUS-FNA associates with increased plasma concentration of cfDNA and increased detection of mutant KRAS after the procedure (markers of tumoremia and possible new distant metastasis). Although levels of cfDNA and activating mutations in KRAS are logical markers of tumoremia, they may not serve as the ideal biomarkers of this process. These findings are preliminary and do not indicate a need to modify current practice, yet further studies are needed.

Feasibility and safety study of 22-gauge endoscopic ultrasound (EUS) needles for portal vein sampling in a swine model

“…Levy et. al then used 22 G needles in EUS-guided portal vein sampling in 10 patients 18 . Thus, combining the three studies in the current literature, a total of 57 patients have been evaluated for EUS-guided portal vein sampling without any evidence of bleeding complications.…”

“…After access to the portal vein is obtained and negative suction is applied, blood from the portal vein has to travel the length of the echoendoscope. While larger-gauge needles have not been shown to have clotting issues 5 17 , 22 G needles were found to have “slow” aspiration, which was corrected by adding heparin to the collection tubes 18 . Similarly, our results showed that the saline-coated 22 G needle was incapable of obtaining an adequate quantity of portal vein blood to run a CTC enumeration test due to clotting within the needle.…”

“…Levy et. al added 2 mL (10,000 U) of heparin to Streck tubes, and subsequent molecular analysis testing could not be completed in any of the FIVE blood samples with heparin 18 . In our study, only 100 uL (100 U) was added, which was 1 % the amount used in Levy et.…”

“…However, current literature is limited in regard to the methodology of collecting portal blood samples with EUS. Only three studies have evaluated EUS-guided portal vein sampling, and each study used different needle sizes including 19-gauge EUS-fine-needle aspiration (FNA) needles, 20-gauge to 21-gauge EUS-FNA needles, and 22-gauge EUS-FNA needles 5 17 18 19 .…”

Impact of preoperative EUS-guided FNA for pancreatic cancer on overall and cancer-free survival: Is the jury still out?

“…The same investigators took this important observation a few steps further and tested the hypothesis that FNA of pancreatic tumors induces "tumoremia" (ie, shedding of cellular and nuclear components into the circulation) and contributes to distant metastases. 10 Blood samples from patients undergoing EUS-FNA of primary pancreatic tumors were collected before and after sampling and were checked for cell-free DNA (cfDNA). Primary tumor samples and plasma cfDNA were evaluated for the presence of K-ras mutations.…”