Significance of 5-Aminolevulinic Acid-mediated Photodynamic Diagnosis Following Standard Transurethral Resection in Non-muscle Invasive Bladder Cancer

Background/Aim: Transurethral resection of bladder tumors (TURBT) guided by photodynamic diagnosis (PDD) with 5-aminolevulinic acid (5-ALA) has been shown to be superior to conventional white light (WL) cystoscopy with regard to diagnostic accuracy, for non-muscle invasive bladder cancer (NMIBC); however, PDD is usually performed prior to WL TURBT. The objective of this study was to investigate the diagnostic significance of 5-ALA-mediated PDD following TUR of NMIBC. Patients and Methods: In 83 NMIBC patients, all visible tumors were completely resected under the conventional WL guidance followed by additional resection if fluorescent lesions were observed under the blue light (BL) guidance, and random biopsy was further conducted. Results: With the BL source, 39 (47.0%) patients were judged to have fluorescent lesions. Twenty (51.3%) of the 39 patients with positive findings by PDD were diagnosed with residual cancer by additional resection, while random biopsy detected cancers in 2 (4.5%) of the 44 patients with negative findings by PDD. Accordingly, the sensitivity, specificity, positive predictive value and negative predictive value in diagnosing residual cancer by our PDD system were 90.9, 68.9, 51.3 and 95.5%, respectively. Univariate analysis showed that the presence of residual cancers shown by WL TURBT was significantly associated with the preoperative findings of urinary cytology, tumor multiplicity, pathological T stage and tumor grade, of which only the preoperative finding on urinary cytology was shown to have an independent impact on the diagnosis of residual cancer. Conclusion: 5-ALA-mediated PDD following standard WL TURBT could improve the diagnostic accuracy in NMIBC patients, particularly those who are positive for preoperative urinary cytology.