Novel photodynamic diagnosis of bladder cancer: ex vivo fluorescence cytology using hypericin

In this study we have evaluated the use of hypericin ex vivo urine fluorescence cytology as a non-invasive method for detecting early bladder cancers. To date this is the first study reported using this technique with hypericin. Urine samples from patients with early bladder cancers were processed for fluorescence cytology by incubation with hypericin, a novel photosensitizer. Normal urine samples incubated with hypericin served as normal controls. Laser confocal microscopy and spectroscopy was used to detect the fluorescence in the exfoliated low-grade urothelial tumor cells. Fluorescence cytology was considered positive if hypericin fluorescence of the low-grade urothelial tumor cells was detected to be stronger (>8.5 times) compared to the baseline fluorescence established for normal urine samples. Automated analysis for an objective reproducible outcome appears possible. The possibility of detection of malignant urothelial cells in early cancer makes ex vivo fluorescence cytology promising for routine diagnostic screening.