Photodynamic therapy
Sunday 28 December 2008, prof. Peter Mlkvý, M. D., Ph. D.
Photodynamic therapy (PDT) for the treatment of Barrett´s esophagus with high-grade dysplasia (HGD).
Endoscopic ablation therapy is an alternative to surgery for the treatment of Barrett´s esophagus with HGD. PDT is one of these ablative therapies. The method is based on the principle of excitation of a photosensitizer by a light of a specific wavelenth. Prior the illumination a photosensitizer (e.g. aminolevulinic acid- ALA) is administered i.v. For reasons not yet clearly understood, the sensitizer is selectively retained at a higher concentration by neoplastic tissue. Excitation of the photosensitizer by a light leads to destruction of sensitized cell via creation of singlet oxygen. Complete eradication of the dysplastic tissue can be achieved in 70 to 80 % of patients. It is on clear why some patients do not respond to this therapy.
