IN-VIVO FLUORESCENCE DETECTION OF OVARIAN-CANCER IN THE NUTU-19 EPITHELIAL OVARIAN-CANCER ANIMAL-MODEL USING 5-AMINOLEVULINIC ACID (ALA)

The purpose of this study was to determine whether in vivo fluorescenc e detection of protoporphyrin IX (PpIX) could be used to identify intr aperitoneal micrometastases of epithelial ovarian carcinoma after appl ication of 5-aminolevulinic acid (ALA), ALA was applied intraperitonea l at different concentrations (25, 50, and 100 mg/kg) and iv (100 mg/k g) to immunocompetent Fischer 344 rats bearing a syngeneic epithelial ovarian carcinoma. At different time intervals after ALA administratio n (1.5, 3, and 6 hr) the peritoneal cavity was illuminated with ultrav iolet (uv) light. In vivo fluorescence of PpIX initially was determine d by direct visualization. Subsequently ex vivo measurements were made with a slow-scan, thermoelectrically cooled CCD camera. Red in vivo f luorescence was observed in ovarian micrometastases smaller than 0.5 m m in 100% of the ALA-administered animals independent of time interval , drug concentration, or route of administration. The intensity of the fluorescence was concentration dependent as strong fluorescence was c onsistently found only above 25 mg/kg ALA. Ex vivo tumor to peritoneum fluorescence yield peaked 3 hr after administration of a 100 mg/kg in traperitoneal dose. Direct visualization of in vivo fluorescence after ALA application may improve the detection of intraperitoneal ovarian cancer micrometastases. (C) 1997 Academic Press.