Advantages of laserphyrin compared with photofrin in photodynamic therapy for bile duct carcinoma

AbstractBackgroundThe aim of this study was to compare the effects of laserphyrin‐PDT (L‐PDT) on biliary cancer with those of the conventional photosensitizer, photofrin‐PDT (P‐PDT).MethodsAn animal tumor model was established by inoculation of NOZ cells in 4‐week‐old male BALB/c mice. The laser light wavelength was set at 630 nm for P‐PDT and 660 nm for L‐PDT, at a frequency of 10 Hz. Each group received a total energy flux of 60 J/cm2. The proportion of TUNEL (terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick‐end labeling)‐positive cells, expression of VEGF (vascular endothelial growth factor) and the PCNA (proliferating cell nuclear antigen)‐labeling index (LI) were assessed after PDT.ResultsL‐PDT had significantly more potent apoptotic effects at 48 and 72 h after light exposure compared with P‐PDT (p < 0.001). The mean PCNA‐LI was significantly lower in the L‐PDT group than the P‐PDT group and the index was significantly lower at several time points after PDT (6, 12, 24, 48 and 72 h after laser light exposure) in the L‐PDT than P‐PDT (p < 0.001 vs. control). The cell proliferative activity was significantly decreased at 12 and 24 h after P‐PDT compared with the control (p < 0.001). VEGF expression was significantly higher at 3 h after L‐PDT compared with the control (p < 0.05), whereas it was significantly higher at many time points after P‐PDT (3, 6, 48 and 72 h;p < 0.05 vs. control).ConclusionsL‐PDT is a better approach for biliary cancer than the conventional P‐PDT, based on its potent apoptotic and cytostatic effects.