Impact of Bladder Neck Involvement on Recurrence in Patients With Non-muscle-invasive Bladder Cancer: An Analysis Based on a Time-dependent Model.

Tumor location in bladder neck has reported to be a prognostic factor for non-muscle-invasive bladder cancer (NMIBC). We investigated the impact of bladder neck involvement (BNI) on recurrence in NMIBC using time-dependent covariate analysis.

We enrolled 585 Japanese patients who underwent transurethral resection for bladder tumors at a single center from 2000 to 2016 and were pathologically diagnosed with Ta and T1 NMIBC. Each patient at each recurrence was assigned to a separate time-dependent stratum with its own baseline hazard function according to the Prentice-Williams-Peterson gap time model for analyzing recurrent events.

Over a median follow-up period of 41.3 months (interquartile range, 18.0-82.3 months), 253 (43.2%) patients experienced a total of 475 recurrences. Among the 1001 total transurethral resection procedures, BNI was observed in 122 (12.2%) cases. The 3-year cumulative recurrence rates of patients with and without BNI were 62.5% and 46.3%, respectively. Multivariable analysis revealed that number of tumors ≥ 4 (sub-hazard ratio [SHR], 1.48; P = .004), intravesical bacillus Calmette-Guérin therapy (SHR, 0.44; P < .001), and BNI (SHR, 1.59; P = .004) were all independent predictors of recurrence. Assigning 1 point for each of these 3 predictive factors, the resulting scores enabled us to classify patients into 3 prognostic groups that were clearly stratified according to recurrence.

Our time-dependent covariate analysis shows that BNI is a significant risk factor for recurrence in NMIBC. Our prognostic model incorporating BNI is an easy means of estimating recurrence risk and determining optimal management for individual patients.

Clinical genitourinary cancer. 2019 Oct 16 [Epub ahead of print]

Yuma Waseda, Shuichiro Kobayashi, Eiichiro Kanda, Minato Yokoyama, Junichiro Ishioka, Yoh Matsuoka, Kazutaka Saito, Yasuhisa Fujii

Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan., Department of Urology, Tama-Nambu Chiiki Hospital, Tokyo, Japan., Department of Medical Science, Kawasaki Medical School, Okayama, Japan., Department of Urology, Tokyo Medical and Dental University Graduate School, Tokyo, Japan. Electronic address: .