LASER-INDUCED AUTOFLUORESCENCE DIAGNOSIS OF BLADDER-CANCER

Purpose: We assessed the ability of laser induced autofluorescence to differentiate malignant from nonmalignant bladder lesions. Materials a nd Methods: We studied 53 patients with bladder cancer undergoing muco sal biopsies or transurethral resection of a bladder tumor. A quartz o ptical fiber was advanced through the working channel of a cystoscope and placed in gentle contact with the bladder. Tissue fluorescence was excited by 337 nm. light pulses (nitrogen laser). One fiber was used for transmission of the excitation and emission (fluorescence) light. An optical multichannel analyzer system was used to record fluorescenc e spectra of the sites of interest. Results: We analyzed the fluoresce nce spectra of 114 bladder areas (1 carcinoma in situ as well as 28 ma lignant, 35 inflammatory, 7 dysplastic, 1 squamous metaplastic and 42 normal areas). These lesions included 44 difficult to diagnose suspici ous tumors (11 malignant and 33 nonmalignant). We developed an algorit hm that used the I385:I455 nm. fluorescence ratio to distinguish malig nant from nonmalignant lesions, including inflammatory areas. By analy zing the data on all 114 lesions, we noted the sensitivity, specificit y, and positive and negative predictive values of this method for diff erentiating malignant from nonmalignant bladder lesions to be 97, 98, 93 and 99%, respectively. Conclusions: Under excitation with 337 nm. l ight a clear differentiation between malignant and nonmalignant bladde r tissues can be made using the I385:I455 nm. autofluorescence ratio.