International Bladder Cancer Group Intermediate-risk Non-muscle Invasive Bladder Cancer (IBCG IR-NMIBC) Scoring System Predicts Outcomes of Patients on Active Surveillance.

Abstract

To determine if the International Bladder Cancer Group (IBCG) intermediate risk (IR)-NMIBC scoring system can predict the requirement of delayed transurethral resection of bladder tumor (TURBT) in low grade (LG) non-muscle invasive bladder cancer (NMIBC) managed by active surveillance (AS). A prospective study of recurrent LG Ta/T1 NMIBC patients managed with AS with the following characteristics were used: LG papillary NMIBC, ≤5 apparent LG NMIBC, tumor diameter ≤1 cm, absence of gross hematuria and negative urinary cytology. Subsequent TURBT was offered to patients who no longer met the inclusion criteria or patient choice. The ability of the IBCG IR-NMIBC scoring system to predict receipt of subsequent TURBT was determined. Multivariable Cox proportional-hazards analysis was used to determine factors associated with subsequent TURBT. A total of 163 patients with LG Ta/T1 NMIBC were included for analysis. After a median follow-up of 33 months (21-46), TURBT was performed on 109 patients. At landmark timepoint of 24 months, patients with 0 RF factors were over two-fold more likely to continue AS compared to patients with ≥3 RF (59% versus 24%). Multivariable Cox regression suggest that the IBCG IR-NMIBC scoring system was associated with subsequent TURBT (1-2 RF [HR: 1.66, 95% CI: 0.96-2.90, P = .072], ≥3 RF [HR: 3.21, 95% CI: 1.70-6.09, P < .001]) after adjusting for age, T-stage and sex. The IBCG IR-NMIBC scoring system can predict the risk of a subsequent TURBT in patients with LG NMIBC on AS.