Use of photodynamic therapy in malignant lesions of stomach, bile duct, pancreas, colon and rectum.

Photodynamic therapy (PDT) using sensitizer, light and oxygen can induce malignant cells to death and treat non-cancerous conditions. It is a predominant and attractive endoscopic technique which could palliate advanced gastrointestinal cancer and eradicate early neoplastic and pre-neoplastic lesions. After PDT, cells may become apoptotic or necrotic which depends on photosensitizer, dose and cells' genotype. Photosensitizers, used in PDT, are accumulated in mitochondria. This is the mechanism of cell death both in vitro and in vivo. In review we summarize the clinical use of PDT in malignant lesions of stomach, bile duct, pancreas, colon and rectum with various photosensitizers. Especially, porfimer sodium, a PDT photosensitizer, has been confirmed as a potent treatment in cholangiocarcinoma.