Upstaging after TUR-BT for non-muscle invasive cancer of the bladder - Who is at highest risk?

IntroductionTransurethral resection of the bladder (TUR-BT) is the standard initial treatment and diagnosis of bladder cancer (BC). Of note, upstaging into muscle-invasive disease (MIBC) during re-resection occurs in a significant proportion of patients. This study aims to define risk factors at initial TUR-BT for upstaging.MethodsTUR-BT between 2009 and 2021 were retrospectively screened (n=3237). We included patients with visible tumors that received their primary and re-TUR-BT at our institution. Upstaging was defined as pathological tumor stage progression into MIBC at re-TUR-BT. Clinicopathological variables were analyzed for the impact on upstaging.Results266 patients/532 TUR-BTs were included into the final analysis. Upstaging occurred in 7.9% (21/266) patients. Patient with upstaging presented with pT1 and pTa NMIBC at primary resection in 85.7% (18/21) and 14.3% (3/21), respectively. Detrusor muscle at primary TUR-BT was significantly less present in patients with upstaging (4.1%vs.95.9%;p<0.001). After multivariate analysis solid tumor configuration (HR4.17; 95%CI 1.23-14.15;p=0.022) and missing detrusor muscle at initial TUR-BT (HR3.58; 95%CI 1.05-12.24;p=0.043) were significant risk factors for upstaging into MIBC.ConclusionsThe current study defined two major risk-factors for upstaging: missing detrusor muscle and solid tumor configuration. We propose that a second resection should be performed earlier if these risk-factors apply.