Intraperitoneal blue LED irradiation as a potential approach to suppress gastric cancer peritoneal dissemination in a murine model.

Peritoneal dissemination remains a critical factor associated with a poor prognosis in gastric cancer. Blue light irradiation has recently been reported to exert wavelength-specific cytotoxic effects on cancer cells. This study evaluated the feasibility, safety, and antitumor efficacy of intraoperative intraperitoneal blue LED (IPBL) irradiation using a murine gastric cancer peritoneal dissemination model. BALB/c nude mice were intraperitoneally inoculated with HGC27 cells and treated with IPBL irradiation via a cylindrical fiber-optic diffuser. Tumor burden was quantitatively assessed by total tumor weight and peritoneal carcinomatosis index (PCI), and perioperative safety was evaluated by clinical findings, serum biochemistry, histopathology, and scanning electron microscopy. The total PCI was markedly reduced in the IPBL group in comparison to the control group (7.2 ± 6.9 vs. 21.3 ± 3.1, P < 0.01). No procedure-related mortality, ascites formation, or macroscopic peritoneal damage was observed. Histological analyses demonstrated preservation of the mesothelial layer, although mild submesothelial collagen deposition and mesothelial flattening were noted. These results indicate that IPBL irradiation is a feasible and well-tolerated intraoperative intervention that significantly suppresses peritoneal dissemination in a murine gastric cancer model and may serve as a promising surgical adjunct to reduce postoperative peritoneal recurrence.