1Department of Thoracic Cardiovascular Surgery, Toho University School of Medicine, 6-11-1 Omorinishi, Tokyo 143, Japan, 2Department of Pathology, Toho University School of Medicine, 6-11-1 Omorinishi, Tokyo 143, Japan, 3Department of Pharmacology, Toho University School of Pharmaceutical Science, 2-2-1 Miyama, Funabashi-shi, Chiba 274-8570, Japan, 4Center Research Laboratory, Hitachi Co., Ltd., Higashikoigakubo, Kokubunji-shi, Tokyo 185-8601, Japan
Sonodynamic therapy is a target therapy that destroys cancer by ultrasound and leaves hematoporphyrin derivative (HpD) intact. We administered this therapy to rats with breast cancer chemically induced by DMBA. Tumor volumes of four treatment groups of rats were compared. The first group was treated only with administration of hematoporphyrin D; the second, with ultrasound irradiation alone; and the third, with a combination of hematoporphyrin D and ultrasound irradiation. The fourth group, the controls, received no treatment. Ultrasound irradiation alone slightly suppressed tumor growth, while hematoporphyrin D alone had no inhibitive effect on tumor growth. Suppression of tumor growth by combined administration of hematoporphyrin D and ultrasound irradiation was remarkable, however. Destruction of tumor tissue was also observed by light microscopy in the cases treated with combined ultrasound irradiation and HpD. We confirmed that the concentration of HpD was higher in the tumor tissue than in the surrounding tissue of the DMBA rats. Sonodynamic therapy appears to offer great promise as a treatment for breast cancers and other cancers that occur near the surface of the body.