Diagnosis and Treatment of esophageal carcinomas and gastric cancers with HpD Administration and Laser photoradiation

Hematoporphyrin derivative (HpD) is a substance that is retained longer by malignant tissue than by normal tissue. It is a fluorescent substance and also has cytocidal effects when stimulated by light. Making use of these three properties the authors applied HpD in the diagnosis and treatment of malignant tumors of the upper G. I. tract by means of an endoscopic and laser photostimulation system. Materials included 9 esophageal carcinomas and 22 gastric cancers. Fluorescence was recognized at the site of tumor in 21 out of 22 tumors. However it was impossible to recognize fluorescence at the site of bleeding or areas covered by necrotic tissue. Therapeutically, complete remission was recognized endoscopically in 8 of 16 early stage cases. Of these, 6 were later resected and pathological examination showed complete disappearance of the tumor in 4. The fact that tumor nests remained in the other 2 was thought to be due to the difficulty in providing homogenous light stimulation. Therefore this method holds promise for the curative treatment of early stage G. I. cancer provided that further development is made in the light delivery capabilities.