Abstract 2877: Enhancing diagnostic precision in peritoneal cancer metastasis: Photodynamic diagnosis-guided laparoscopy in a rabbit model

Abstract

Abstract Introduction: Precise diagnostic workup is crucial for developing effective treatment strategies in cancer patients. Peritoneal carcinomatosis, often missed in preoperative CT scans and conventional laparoscopy, poses diagnostic challenges. This study aimed to assess the diagnostic accuracy of staging laparoscopy using photodynamic diagnosis (PDD) with the photosensitizer phonozen activated at 405 nm in a rabbit model of peritoneal carcinomatosis. Methods: Female New Zealand white rabbits (16-20 weeks old) were utilized to establish the model through peritoneal inoculation of VX2 sarcoma cells, resulting in distinct solid-tumor nodules for laparoscopic evaluation. A customized dual-emission laparoscope, capable of both white-light and 405 nm blue-light, was employed for PDD. To minimize blue-light background interference, a 550 nm long-pass filter was placed between the laparoscope and the video camera, optimizing the process. The PDD-enhanced diagnostic laparoscopy comprised a tripartite approach: 1) initial peritoneal cavity exploration under white-light and labeling of suspect nodules, followed by 2) utilization of blue light with the long-pass filter to identify red-light emissions from distinctly labeled tumor cells, and 3) open laparotomy served to palpate the peritoneal surface and identify additional or missed tumor nodules. Results: Analysis of data from 12 rabbits with 267 tumor nodules revealed that sensitivity and specificity of diagnostic laparoscopy for detecting tumor nodules increased from 84.9% and 18.8% with white light alone to 90.8% and 25.0% when aided by PDD, respectively. These findings underscore the substantial improvement in diagnostic accuracy achievable by combining the rabbit model of peritoneal carcinomatosis with PDD in laparoscopic procedures. Conclusion: The heightened sensitivity and specificity observed in this study hold significant promise for positively impacting clinical practice, providing a more accurate and effective approach to the diagnosis and management of peritoneal carcinomatosis. Citation Format: Hyoung-Il Kim, Adriana Rivera-Piza, Sunghwan Lee. Enhancing diagnostic precision in peritoneal cancer metastasis: Photodynamic diagnosis-guided laparoscopy in a rabbit model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2877.