Photodynamic destruction of human bladder carcinoma

Eleven human bladder carcinomata of different degrees of differentiation were implanted in mice immunosuppressed by thymectomy, anti-thymocyte serum and x-rays. Seven carcinomata grew well and one poorly and 3 produced mainly fibrous nodules in the mice. Normal human bladder tissues were grown from 4 other patients. The administration of a haematoporphyrin derivative (HpD), followed 24 h later by exposure to white light, caused marked destruction of tumours but little or none of normal bladder tissues. HpD or light alone caused no damage to tumours or normal tissues. It is suggested that photodynamic therapy may be applicable in the treatment of superficial transitional cell carcinoma of the bladder.