ABSTRACT
BACKGROUND: Photodynamic therapy (PDT) of hepatic tumors has been restricted due to the preferential retention of photosensitizers in normal liver tissue. Therefore, superficial tumor illumination causes subsequential liver necrosis. Moreover, the limited light penetration during superficial illumination makes it impossible to treat deep-seated or larger solid tumors. These limitations were overcome by interstitial therapy. Aim: The aim of study is to investigate the macroscopic and microscopic effect of a single session of interstitial photodynamic therapy on liver tumor. METHODS: The Morris 7777 hepatoma cells were injected subcutaneously into the flanks of Buffalo female rats. Tumor growth was monitored with measuring the tumor size. Animals were pretreated with hematoporphyrin derivative 48 hours prior to the intratumoral delivery of laser radiation, when the tumor had reached a volume greater than 1.0 cm3. One or two weeks after interstitial PDT, the extent of tumor necrosis was evaluated microscopically. RESULTS: Volume of lesions averaged 10.2 mm3. Histologic stains demonstrated microvascular thrombosis and coagulative necrosis within the lesions. There appeared to be 100% cellular destruction within the lesion by cytochemical staining. CONCLUSION: The results of this study show the ability of interstitial PDT to cause destruction of liver tumor.