The Significance Intra-operative Photodynamic Therapy (PDT) for Advanced Gastrointestinal Cancer

Abstract

Laser has been clinically used only for hemostasis under an endoscope in the early period since laser was developed in Japan in the late 70th. In our department it has been used mainly for endoscopic lithotripsy of bile duct stones and endoscopic treatment for gastrointestinal tumors. Because intra-operative PDT has been used recently as a new aspect of laser treatment, the significance was examined in this study. The clinical results of follow up study on esophageal cancer shows this therapy is effective for shallow cancer. Local recurrence of esophageal cancer somethimes occurs even in the case of n (-) or with the waide dissection of lymphnodes. The reason would be partly due to micro invasion in surrounding connective tissue. PDT would be useful for this residual micro invasion. On the other hand, as to rectal cancer, as the nerve-preserved method has been recommended in recent years PDT would be also useful for the nerve preserved area. In the study of seven cases of esophageal cancer the mean level of photo sensitive material was 2 times higher (117.4±28.5ng/100mg) in cancer tissue than in normal esophageal mucosa (66.7±12.8ng/100mg). This therapy has an advantage easily to use in an operating room compared with intra-operative radio therapy, However, the photosensitive material has a little bit of sideeffects, and more effective laser are not available. The prompt improvement and develop,ent are expecting.