Effects of photodynamic hyperthermal therapy with indocyanine green on tumor growth in a colon 26 tumor-bearing mouse model

The present study used indocyanine green (ICG) and a broadband light source apparatus [photodynamic hyperthermal therapy (PHT) group] in order to treat a colon 26 tumor-bearing mouse model. The other groups were administered either ICG alone (ICG group), light alone (light group) or no treatment (control group). Following the treatment, tumor growth was measured. Nine days after the treatment, the tumors were resected and histological and immunohistological examinations were performed. In the PHT group, the growth rates of the tumor tissues were significantly decreased compared with those observed in the other groups (P<0.05). The proportion of necrotic areas in the PHT and light groups were increased significantly compared with those observed in the ICG and control groups. However, there were no significant differences between the PHT and light groups. The proportion of Ki-67 in the PHT and light groups was less than that observed in the ICG and control groups. The number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling-positive cells in the PHT group was significantly increased compared with that observed in the other groups. These data indicate that PHT is effective in vivo and in vitro.