Abstract

In at least 60% of cases human bladder cancer grows multifocally. In addition to the macroscopically recognizable foci many tiny foci may be present, too small to be diagnosed endoscopically. These microfoci effectively determine the course of the disease. Conventional therapeutic methods including thermal Nd:YAG-laser coagulation of the tumor tissue are not able to deal successfully with this part of the tumor. Untreated carcinoma in situ is at least in part responsible for the 80% rate of tumor recurrence during the first 24 months.¹ Hematoporphyrin derivative (HpD) is selectively stored in various tumors including both experimental and human bladder carcinoma.¹ After intravenous application (2–5 mg/kg of body weight) HpD causes photosensitization of tissue. Light exposure, for example, red light from a dye laser, induces cytotoxic effects in the photosensitized material. Thus tumor cells can be selectively destroyed by photoradiotherapy (PRT). Normal HpD-free tissue is not affected by the laser irradiation.

© 1984 Optical Society of America