Photodynamic Therapy for Gastrointestinal Cancer in the Elderly

Photodynamic therapy (PDT) is one of a cancer treatment which use a photosensitizer and a laser devise. Photosensitizers generate singlet oxygen which involves cellular apoptosis under oxidative stresses. Since photosensitizers such as porphyrins and/or chlorins used to be particularly accumulated into cancer cells, PDT is able to derive a cancer specific cell death. Moreover, photosensitizers refer to be fluorescent substances, their cancer specific localization help us a clue to diagnose the lesion’l area; it is so-called photodynamic diagnosis (PDD). However, patients after PDT should continue to be hospitalized for 2wks in a dark room to prevent photo-hypersensitivity. Nowadays, the confirmed therapy for the early-staged gastric cancer is thus endoscopic sub-mucosal dissection (ESD). Nevertheless, almost all countries are changing into aging countries. For the preventions for heart and brain vascular diseases, aged persons used to take anti-platelet reagents which are taboos for ESD. Since PDT involves thrombus in the micro-vascular in the laser-irradiated area, the risk of hemorrhages is less than ESD for the antithrombotics taking patients. Actually, in the cases of Tsukuba University Hospital, almost all aged patients showed good outcomes without any severe complications. We believe PDT is an answer for the cancer treatment with senior aged patients.