Morphological effects of photodynamic therapy on rabbit bladder using Photofrin II and Photosan intravesically and intravenously.

Photodynamic therapy (PDT) has proved effective against superficial papillary bladder tumours and focal and diffuse carcinoma in situ. Effective topical administration of the sensitiser would be a welcome improvement. The morphological effects of PDT on the normal bladder were examined in 13 rabbits when 2 photosensitisers (Photofrin II and Photosan III) were applied intravesically (5 mg/kg for 1 h) and compared with intravenous administration (3 or 5 mg/kg). Four animals served as controls without a sensitiser. Intravesical red light (630 nm) from an argon dye laser was used to activate the photosensitiser, using light doses of 12 or 24 J/cm2. The animals were sacrificed either 1 or 5 to 7 days after the laser treatment. Intravenous dosage induced bladder wall oedema/haemorrhage and total necrosis of the epithelium. There was no difference between the effects of the 2 sensitisers. Intravesical application induced superficial epithelial necrosis. The control animals treated with laser light alone showed slight superficial injury to the cell layer.