Photodynamic therapy: the state of the art.

Photodynamic therapy is a new and exciting treatment modality for many forms of localised malignant disease. A considerable amount of laboratory and clinical research has been carried out using the tumour sensitiser haematoporphyrin derivative activated by red light at a wavelength of 630 n commonly produced by either an argon/dye laser or a pulsed gold vapour laser. It appears certain that continuing research will produce better tumour sensitisers activated by different wavelengths of light, but it will be several years before any new drug/light combination is ready for clinical trials. This paper presents an overview of the current situation and a summary of some of the exciting results that are being obtained in clinical trials throughout the world.