Fluorescence cytology of the urinary bladder

To assess, on the basis of the tumor-associated fluorescence characteristics of 5-aminolevulinic acid-induced fluorescence endoscopy, the value of fluorescence microscopy and compare it with standard cytologic techniques. 5-Aminolevulinic acid-induced fluorescence endoscopy has proved to be a valuable detection method with a high sensitivity for the endoscopic diagnosis of bladder cancer.

We instilled 1.5 g of 5-aminolevulinic acid, dissolved in 50 mL of 5.7% sodium monohydrogen phosphate, into the urinary bladder of 162 patients with suspected transitional cell carcinoma 2 to 3 hours before endoscopy. A lavage solution was obtained for urinary cytology and for fluorescence cytology. The sediments were evaluated for tumor cells.

Transitional cells suspicious for tumor demonstrated the red 5-aminolevulinic acid-induced protoporphyrin IX fluorescence under the microscope. Fluorescence cytology identified 50 of 58 histologically confirmed neoplastic lesions (G1, 14 of 17; G2, 12 of 14; G3, 15 of 16; and carcinoma in situ, 9 of 11). With urinary cytology, we identified 46 of 58 histologically confirmed tumor lesions (G1, 9 of 17; G2, 12 of 14; G3, 15 of 16; and carcinoma in situ, 10 of 11). The sensitivity of fluorescence cytology was 86% and that of urinary cytology 79%. The specificity of fluorescence cytology was 75% and that of urinary cytology 88%.

Fluorescence cytology promises to be an effective procedure for the diagnosis of bladder cancer, especially in highly differentiated and flat premalignant tumor lesions. Automated analysis for an objective and a reproducible result appears possible.