33: Fluorescence-guided Surgery and Adjuvant Photoimmunotherapy Using a Single Fluorescent Antibody Reduces the Frequency of Metastatic Recurrence in an Orthotopic Nude Mouse Model of Pancreatic Cancer

Saturday, March 12, 2022

10:21 AM – 10:29 AM CST

Location: Trinity Ballroom

Abstract Presenter(s)

Michael A. Turner, MD

Surgery resident
University of California, San Diego
San Diego, California, United States

Disclosure: Disclosure information not submitted.

Participants should be aware of the following financial/non-financial relationships:

Hiroto Nishino, MD., PhD: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Introduction: The use of tumor-specific antibodies conjugated to near-infrared (NIR) fluorescent probes has shown to be effective for fluorescence-guided surgery (FGS) and photoimmunotherapy (PIT). We hypothesize that the two methods can be combined to reduce pancreatic cancer recurrence after surgery.

Methods:

Nude mice received surgical orthotopic implantation (SOI) of human pancreatic-cancer cell-line BxPC-3 expressing green fluorescent protein (GFP)s. An anti-carcinoembryonic antigen-related cell adhesion molecule (CEACAM) monoclonal antibody (6G5j) was conjugated to IR700DX (6G5j-IR700DX). Three weeks after SOI, 16 mice received 50μg 6G5j-IR700DX via tail-vein injection 24 hours before surgery and were randomized to two groups: FGS-only (n=8) and FGS + PIT (n=8). All tumors were imaged with the Pearl Trilogy Imaging system and resected under the guidance of the FLARE Imaging System with merged 700 nm and bright-light channels (Figure). The FGS + PIT group received PIT of the surgical bed at an intensity of 150 mW/cm² for 30 min. Mice were sacrificed 4 weeks after initial surgery and tumors were imaged with a Dino-Lite digital microscope, excised, and weighed.

Results:

6G5j-IR700DX brightly illuminated the orthotopic pancreatic tumors for FGS and PIT. The local recurrence rate was 100.0 % for FGS-only and 50.0 % for the combination of FGS + PIT (p = 0.077). The metastatic recurrence rate was 100.0 % for FGS-only and 25.0 % for FGS + PIT (p = 0.007). The average total recurrent tumor weight was 2370.3 ± 1907.8 mg for FGS-only and 705.5 ± 1200.0 mg for FGS + PIT (p = 0.039).

Conclusions:

FGS and adjuvant PIT can be combined by using a single antibody-fluorophore conjugate (6G5j-IR700DX). In this study, FGS combined with PIT could significantly reduce the frequency of metastatic recurrence and the total weight of recurrent tumors of pancreatic cancer.

Learning Objectives:

learn the significance of fluorescence-guide surgery.
learn the significance of photoimmunotherapy.
learn the significance of the combination of fluorescence-guide surgery and adjuvant photoimmunotherapy.