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

Abstract

BackgroundIntermediate-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. ObjectiveWe investigated the role of BNI in risk substratification of intermediate-risk NMIBC patients. Design, setting, and participantsThis single-institutional study included 436 primary or recurrent intermediate-risk NMIBC patients based on risk stratification in the European Association of Urology guidelines. InterventionAll patients underwent transurethral resection of the bladder tumor. Outcome measurements and statistical analysisThe 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 limitationsOverall, 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. ConclusionsBNI 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 summaryThe 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.