Investigation of early cancerous changes in bladder tissue by autofluorescence

Intrinsic fluorescence (autofluorescence) and reflective spectroscopy were used to study precancerous conditions and cancer in vivo in mucosal tissue of urinary bladder. Fluorescence was induced using 370 nm and 400 nm excitation, but 400 nm gave better separation of the groups. Biopsies were taken and frozen sections imaged on a fluorescence microscope with a CCD camera. The in vivo cystoscopy study had 19 patients and the cystectomy study had 35. Peak emission was 460 nm and it decreased with increased severity of disease with a 1.6 decrease from benign mucosal tissue to CIS and 3.2 decrease to invasive cancer. Invasive cancer grouped statistically differently from benign mucosal tissue using 460 nm emission while invasive cancer and CIS grouped statistically differently from benign mucosal tissue using normalized emission at 635 nm. Dysplasia did not group statistically differently from benign mucosal tissue. The fluorophores seem to be collagen and porphyrins. In microscopic images, the predominant fluorophore seems to be collagen fluorescing in blue strands while a secondary fluorophore seems to be inflammatory cells with yellowish-green round spots.