P93. Surgical drain fluid as a novel liquid biopsy source for post-operative staging in pancreaticobiliary cancers

Saturday, March 7, 2026

9:00 AM - 9:07 AM MST

Location: 105A-C

Primary Author(s)

SD

Shakti Dahiya, PhD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Co-Author(s)

LK

Lucien Khalil, MD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States
NT

Nikhil Tirukkovalur, MD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States
HY

Hamza Yazdani, MD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States
SC

Sebastiaan Ceuppens, MD

PhD-researcher
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
AC

Asmita Chopra, MD

Resident Physician
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
ZX

Zhongping Xu, PhD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States
Aatur Singhi, MD PhD

Associate Professor of Anatomic Pathology
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States
KL

Kenneth Lee, MD

Professor of Surgery
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States
AP

Alessandro Paniccia, MD

Assistant Professor of Surgery
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States
Amer H. Zureikat, MD

Professor and Chief, Division of Surgical Oncology
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States
ST

Samer Tohme, MD

Assistant Professor of Surgery
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
ML

Michael Lotze, MD

Professor of Surgery, Bioengineering, and Immunology
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
JZ

Jose Zevallos, MD

University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Primary Presenter(s)

Genia Dubrovsky, MD

Assistant Professor of Surgery
University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Slides

Introduction: Patients with pancreaticobiliary (PB) cancers continue to have poor outcomes at all stages, with frequent recurrences post-operatively. Blood-based liquid biopsy can predict progression, recurrence, and survival, but sensitivity in early-stage disease remains low. To address this low sensitivity and specificity, we investigated surgical drain fluid as a novel liquid biopsy source, as its proximity to the resected tumor and tumor microenvironment may yield higher concentrations of tumor-derived nucleic acids and immune markers.

Methods: In a prospective cohort of patients with PB malignancies who underwent curative-intent surgical resection with pancreatectomy, paired surgical drain fluid and plasma samples were collected on post-operative day 1. Total cell-free DNA (cfDNA) concentrations, circulating tumor DNA (ctDNA) fractional abundance, and neutrophil extracellular traps (NETs) were quantified in the paired samples of blood and drain fluid.

Results: 35 patients with PB malignancies underwent curative-intent resection and had biofluid collected. Drain fluid contained an average of ~400-fold higher concentration of cfDNA than plasma, and 5.7 times higher concentration of NETs than plasma (p< 0.001). ctDNA was detectable in 5/35 patients in drain fluid, and 1/33 patients in plasma. Patients with N2 vs N0 disease, and those with R1 resection vs R0 resection had significantly higher levels of ctDNA (p< 0.05) in drain fluid, but not in plasma. Patients with early cancer recurrence within 1 year of surgery had a significantly higher ratio of plasma NETs relative to total plasma cfDNA (p< 0.05), and had a trend towards significantly higher levels of drain ctDNA and drain cfDNA.

Conclusions: Surgical drain fluid is a rich source of nucleic acids, with greater DNA yield and higher ctDNA detection compared to plasma. It is also a clinically relevant biofluid, with drain fluid ctDNA levels correlating with pathologic features that are predictive of patient survival. Preliminary follow-up data show that plasma NETs help to predict recurrence, and suggest that drain fluid biomarkers can also be predictive of cancer recurrence. Future directions include increasing sample size, and additional characterization of immune-cell populations within this novel biofluid.

Learning Objectives:

Surgical drain fluid is a novel biofluid with distinct characteristics from plasma, such as higher nucleic acid content and higher concentration of NETs in the immediate post-op period.
Higher levels of drain fluid ctDNA correlate with more advanced nodal stage and margin positivity after tumor resection.