Objectives: To establish a new diagnostic method for the detection and follow-up of bladder cancer that combines the principles of photodynamic diagnosis and urinary cytology.
Methods: We investigated 46 patients scheduled for transurethral resection of a bladder tumor immediately before the resection was carried out. After intravesical instillation of either 5-aminolevulinic acid (ALA) or hypericin, urinary cytology specimens were obtained. Induced fluorescence of urothelial cells was detected by fluorescence microscopy. The results were compared with the conventional cytologic and histologic findings.
Results: In the 46 patients, 42 cases of urothelial carcinoma and 4 cases of nonspecific inflammation were diagnosed. Of the 42 patients with cancer, 19 had Stage Ta, 9 had T1, 3 had carcinoma in situ, and 11 had invasive bladder cancer. The grading was G1 in 17 patients, G2 in 6 patients, and G3 in 19 patients. In 38 cases we instilled ALA and in 8 hypericin. All 4 patients diagnosed with nonspecific inflammation had received ALA. We detected ALA-induced fluorescence in 34 of 38 cases. One of the four histologically negative cases had a false-positive finding and 1 case of urothelial carcinoma did not show fluorescence. After instillation of hypericin we could detect induced fluorescence in all cases.
Conclusions: Our first results suggest that fluorescence cytology is more sensitive than other noninvasive tests. After additional investigation, it may become a valuable diagnostic method and may reduce the number of cystoscopies in the follow-up of bladder tumors.