PD50-07 SYSTEMATIC ENDOSCOPIC EVALUATION FALLS SHORT IN PREDICTING PT0 BLADDER CANCER

Abstract

INTRODUCTION AND OBJECTIVE: Concern for discordance between endoscopic evaluation and final pathology drives current clinical management of patients deemed appropriate candidates for radical cystectomy (RC). Yet, > 30% of patients (pts) who undergo neoadjuvant chemotherapy (NAC) prior to RC do not harbor detectable malignancy within the bladder at the time of extirpative surgery. Our objective was to prospectively assess the reliability of cystoscopic evaluation in RC candidates. METHODS: Pts undergoing RC for urothelial carcinoma (UC) at our institution were enrolled in a prospective single-arm study to evaluate reliability of Systematic Endoscopic Evaluation (SEE) in predicting pT0 UC. SEE consisted of rigid cystoscopy with targeted biopsy (and transurethral resection with loop after protocol amendment) of visible tumor and/or tumor bed/scar, plus two additional random biopsies performed at the time of RC. A standardized bladder map was used to index cystoscopic findings. SEE and biopsy results were compared to RC pathology. Comparisons were considered congruent if both SEE and RC were T0, or if any level of disease seen at both SEE and RC (exception, cT0 with pTis at RC called congruent). This trial design included early stopping rules for futility based on the primary endpoint of a negative predictive value (NPV) less than 70%. RESULTS: In total, 61 pts underwent SEE and RC as part of this trial. The final population included MIBC in 41 pts (67%) and high-risk NMIBC in 20 pts (33%). 38 pts (62%) received platinum-based neoadjuvant chemotherapy. Based on RC final pathology, 16 pts (26%) were pT0 and 28 pts (46%) harbored residual ≥pT2 disease. For detecting any disease, the positive predictive value was 96.7%, but the NPV was 48.4%, necessitating study closure based on pre-specified boundaries for futility. The sensitivity for detecting pT2 at RC disease was 71%. CONCLUSIONS: To our knowledge, this was the first prospective study exploring whether a standardized SEE could sufficiently predict the presence of residual malignancy. The NPV was below the pre-specified threshold, triggering study closure. pT2 or higher disease was missed nearly 30% of the time. This study definitively demonstrates that current cystoscopic techniques are inadequate to guide decisions on bladder preservation.Source of Funding: None