title: Photodynamic therapy for gastrointestinal tumors.
abstract: Photodynamic therapy is based on the administration of a compound that is preferentially accumulated by a tumor and which causes tumor destruction after exposure to light of a specific wavelength. The photosensitizers most commonly used in treating tumors of the gastrointestinal tract are porphyrins--hematoporphyrin derivative and dihematoporphyrin ether. These compounds have been used with success to produce reduction in tumor size of esophageal, gastric, and colorectal cancers. In some instances long-lasting complete remission have been observed after photodynamic therapy. New developments include photosensitizers that react to light of a longer wavelength, which is able to penetrate tissue to a greater depth, the use of 5-aminolevulinic acid, which is preferentially converted to porphyrin in malignant cells, and combination of photodynamic therapy with thermic laser, radiotherapy, or chemotherapy.
authors.affiliation: Dept. of Internal Medicine, Erasmus University, Rotterdam, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Wilson
authors.forename: R
authors.initials: R
authors.lastname: van Hillegersberg
authors.forename: J W
authors.initials: JW
authors.lastname: van den Berg
authors.forename: W J
authors.initials: WJ
authors.lastname: Kort
authors.forename: O T
authors.initials: OT
authors.lastname: Terpstra
mesh_terms: D015179:Colorectal Neoplasms / Q000188:drug therapy; D004938:Esophageal Neoplasms / Q000188:drug therapy; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy; D010778:Photochemotherapy