Early Photodynamic Diagnosis Cystoscopy After Bacillus Calmette-Guerin (BCG) Induction for High-Risk Nonmuscle Invasive Bladder Cancer Significantly Increased the Detection of BCG Refractory Tumors

Objectives: To compare the detection rate of Bacillus Calmette-Guerin (BCG) refractory tumors between white light cystoscopy (WL-C) and Photodynamic Diagnosis cystoscopy (PDD-C). Materials and Methods: We performed a monocentric retrospective study that included all consecutive patients with high-risk nonmuscle-invasive bladder cancer (NMIBC) diagnosed from January 2017 to January 2021. All patients had an initial transurethral resection of bladder tumor (TURBT) with photodynamic diagnosisrestaging TURBT if needed, followed by full-dose BCG induction. Within 8 weeks following BCG induction, all patients had both WL-C and PDD-C under general anesthesiaTURBT in case of suspicious lesion. The primary end point was the detection of bladder cancer (BC) at post-BCG cystoscopy. Results: A total of 136 consecutive patients met inclusion criteria. Initial BC characteristics were: 35.6% of T1 tumor, 92.6% high grade, and 48.6% associated CIS. BC was diagnosed in 33/136 cases (24%) at early PDD-C after BCG induction: 77% Ta, 23% T1, 56% associated CIS, 68% high grade, and 6% muscle-invasive bladder cancer. Sensibility and Specificity of WL-C and PDD-C: 41% vs 91% (p<0.001) and 86% vs 75% (p=0.001). PDD-C detected 16 additional tumors: 81.3% Ta, 18.7% T1, 75% associated CIS, and 75% high grade. Conclusions: Systematic use of PDD after BCG induction increased the detection of BCG-refractory tumors and led to significant modification in the treatment of high-risk NMIBC. Future studies are needed to evaluate long-term oncologic benefit of early PDD reevaluation and its cost-effectiveness.