Ultraviolet-excited (308 nm) autofluorescence for bladder cancer detection

To assess the ability of ultraviolet laser-induced autofluorescence for the diagnosis of transitional cell carcinoma of the bladder.

We studied 43 patients undergoing transurethral resection with recurrent transitional cell carcinoma of the bladder. Guided through 5-aminolevulinic acid-induced fluorescence endoscopy, the autofluorescence of the red fluorescing areas and the adjacent tissue and inconspicuous-appearing mucosa were measured spectroscopically. The autofluorescence excitation was carried out with a xenon chloride excimer laser operating at 308 nm (AF308). For the evaluation of the autofluorescence spectra, an intensity ratio (335/430 nm) was calculated and correlated with the histologic results of the biopsies taken.

We analyzed the AF308 spectra of 114 biopsies (21 malignant, 93 benign). The autofluorescence intensity ratios for the benign lesions were a factor of 2 to 7 higher than carcinoma in situ and neoplastic tissue. Therefore, 20 of 21 neoplastic lesions were detected as true positive by AF308. A sensitivity and specificity for AF308 of 95% and 77%, respectively, could be calculated. The sensitivity and specificity for 5-aminolevulinic acid-induced fluorescence endoscopy was 90% and 61%, respectively. By combining the two methods, we calculated a sensitivity of 90% and a specificity of 84%.

The combination of a sensitive imaging technique such as 5-aminolevulinic acid-induced fluorescence endoscopy and a more specific spectral fluorescence probe technique with autofluorescence at 308 nm is a very efficient procedure in the detection of transitional cell carcinoma of the bladder.