Photodynamic Diagnosis(PDD) following Intravesical Instillation of 5-aminolevulinic acid(ALA) for Detection of Neoplastic Urothelial Lesions

Hong, Jeong Hee; Jeon, Seong Soo; Kim, Dae Kyung; Choi, Han Yong; Chai, Soo Eung

Abstract

PURPOSE: Flat urothelial lesions such as high-grade dysplasia and carcinoma in situ and tiny papillary bladder tumors can be overlooked during the conventional cystoscopy. PDD is based on the detection of protoporphyrin IX(PpIX)-induced fluorescence in urothelial cancer epithelium through topical administration of 5-aminolevulinic acid (ALA). This study attempted to evaluate the diagnostic efficacy of PDD in urothelial neoplasms.
MATERIALS AND METHODS
41 patients with suspicion of bladder cancers were investigated by fluorescence-assisted transurethral resection. Intravesical instillation of ALA was done for PDD 2 hours prior to transurethral resection of bladder tumor. A total of 197 tissue samples were obtained from the fluorescing and non-fluorescing areas of the bladder. The correlation between fluorescence findings and histopathological diagnosis were investigated.
RESULTS
All 74 samples which appeared malignant during the conventional cystoscopy were fluorescened strongly in the red, pathologically confirming the tumor. Additional 33 foci of carcinoma(CIS in 12, Ta in 5, T1 in 12, T2 in 4) which were invisible during routine cystoscopy could be detected only by PpIX-induced fluorescence. The sensitivity and specificity can be estimated at 97.0% and 32.3%, respectively. Low specificity may be due to the insufficient number of random biopsies of the normal bladder wall.
CONCLUSIONS
PpIX-induced fluorescence with intravesical instillation of ALA is a feasible and efficient method for mapping the mucosa in the occult urothelial neoplasms. PDD might be helpful in complete resection of flat urothelial lesions and tiny papillary tumors and it would be able to provide helpful information for the appropriate further treatment.