Photochemotherapy of glioma cells by visible light and hematoporphyrin

Malignant tumors take up and retain hematoporphyrin to a much greater extent than do normal tissues. Porphyrins are photodynamic agents that sensitize cells so that they are damaged by exposure to light. Treatment with hematoporphyrin followed by irradiation with light can destroy glioma cells in culture in less than 8 min and gliomas growing s.c. in rats in about 40 min. Photochemotherapy may become useful in the management of malignant tumors that are resistant to current methods of treatment.