Significance of Bladder Neck Involvement in Risk Substratification of Intermediate-Risk Non-muscle-invasive Bladder Cancer

Abstract

Background: Intermediate-risk non-muscle-invasive bladder cancer (NMIBC) involves heterogeneous patients, resulting in uncertainty regarding its prognosis and the indication of adjuvant therapy. Previous studies suggested a correlation between tumor location, especially bladder neck involvement (BNI), and patient prognosis of NMIBC.

Objective: We investigated the role of BNI in risk substratification of intermediate-risk NMIBC patients.

Design, setting, and participants: This single-institutional study included 436 primary or recurrent intermediate-risk NMIBC patients based on risk stratification in the European Association of Urology guidelines.

Intervention: All patients underwent transurethral resection of the bladder tumor.

Outcome measurements and statistical analysis: The primary and secondary endpoints were progression and recurrence, respectively. The associations of BNI with the endpoints were examined using the Kaplan-Meier method and the Cox proportional hazards model.

Results and limitations: Overall, 205 (47%) patients had multiple tumors and 276 (63%) underwent intravesical therapy. BNI was observed in 53 (12%) patients. During the median follow-up of 42 mo, 12 (3%) and 211 (48%) patients experienced progression and recurrence, respectively. Multivariate analysis showed that BNI was an independent predictor for both progression (hazard ratio 10.98, p < 0.001) and recurrence (hazard ratio 2.12, p < 0.001). The progression rate was significantly higher in patients with BNI compared with those without BNI (13% vs 1% at 3 yr and 20% vs 1% at 6 yr; p < 0.001). Analogous findings were observed for recurrence. The progression rate was more remarkably stratified by BNI in 103 recurrent cases (17% vs 3% at 3 yr and 34% vs 3% at 6 yr in patients with vs without BNI; p < 0.001). A limitation of this study was its retrospective nature.

Conclusions: BNI substratified intermediate-risk NMIBC patients well regarding their risks of progression and recurrence, which could help determine follow-up and therapeutic strategies for these patients.

Patient summary: The associations of bladder neck involvement with progression and recurrence were evaluated in patients with intermediate-risk non-muscle-invasive bladder cancer. We found that bladder neck involvement was a good factor for substratifying patients based on their risks of progression and recurrence. Bladder neck involvement can be useful in determining follow-up and therapeutic strategies for intermediate-risk non-muscle-invasive bladder cancer.

Keywords: Bladder neck involvement; Non–muscle-invasive bladder cancer; Progression; Risk substratification.