Background
Our laboratory has previously developed fluorescence-guided (FGS) of pancreatic and other cancers in orthotopic mouse models. Laparoscopic surgery is being used more extensively in surgical oncology. The present report describes the efficacy of laparoscopic FGS of pancreatic cancer in an orthotopic mouse model.
Study Design
Mouse models of human pancreatic cancer were established with fragments of the BxPC-3 RFP human pancreatic cancer using surgical orthotopic implantation (SOI). Mice were randomized to bright light laparoscopic surgery (BLLS) or to fluorescence guided laparoscopic surgery (FGLS). FGLS was performed with an LED light source through a 495-nm emission filter in order to remove the primary tumors and any additional separate sub-millimeter deposits within the pancreas, the latter of which was not possible with BLLS. Tumors were labeled with anti-CEA-Alexa 488 antibodies 24 hours before surgery with intravenous injection. Perioperative fluorescence images were obtained to evaluate tumor size. Mice were followed postoperatively to assess for recurrence and at termination to evaluate tumor burden.
Results
At termination, the FGLS group had less pancreatic tumor volume than the BLLS group (5.75 mm2 vs 28.43 mm2, respectively; p=0.012) and lower tumor weight (21.1 mg vs 174.4 mg, respectively; p=0.033). FGLS compared to BLLS also decreased local recurrence (50% vs 80%, respectively; p=0.048) and distant recurrence (70% vs 95%, respectively; p=0.046). More mice in the FGLS than the BLLS group were free of tumor at termination (25% vs 5%, respectively). The median disease free survival (DFS) was lengthened from 2 weeks with BLLS (95% CI [1.635, 2.365]) to 7 weeks with FGLS (95% CI [5.955, 8.045]) (p=0.001).
Conclusions
FGLS is more effective than BLLS, and therefore has important potential for surgical oncology.