Contemporary Staging for Muscle-Invasive Bladder Cancer: Accuracy and Limitations.

Overview

abstract

CONTEXT: Bladder cancer prognosis and treatment are heavily dependent on accurate staging. Traditional imaging and pathologic evaluation of transurethral resection (TUR) specimens have been associated with high rates of clinical understaging at the time of radical cystectomy (RC). OBJECTIVE: We describe current components and limitations of bladder cancer staging for muscle-invasive bladder cancer (MIBC), and discuss the rationale for inclusion of novel biomarkers and imaging modalities to improve diagnostic accuracy. EVIDENCE ACQUISITION: We summarize the data informing MIBC staging accuracy using a nonsystematic review of published literature and provide expert opinion on current and emerging standards in MIBC staging. EVIDENCE SYNTHESIS: Nearly 50% of patients undergoing RC are clinically understaged preoperatively. Components of clinical staging include TUR specimen evaluation, bimanual examination under anesthesia (EUA), and cross-sectional imaging of the chest, abdomen, and pelvis. Complete endoscopic resection of visible disease with sampling of muscularis propria is indicated. While histologic features such as tumor size, focality, variant histologic differentiation, and lymphovascular invasion have prognostic utility, insufficient evidence exists to incorporate them into current staging paradigms. For primary tumor staging, conventional computed tomography (CT) has limited accuracy in differentiating non-MIBC from MIBC. Magnetic resonance imaging (MRI) has exhibited superior pT staging accuracy with the validated Vesical Imaging Reporting and Data System. Positron emission tomography (PET)/CT does not increase clinical nodal staging accuracy beyond CT or MRI, and there exists no consensus role for the use of PET in routine clinical staging. CONCLUSIONS: In the absence of reliable biomarkers to serve as staging adjuncts, we continue to rely heavily on basic clinical staging components-TUR with accurate pathologic evaluation, EUA, and standard cross-sectional imaging modalities. MRI shows promising accuracy and interobserver reliability for primary tumor staging. PATIENT SUMMARY: Effective clinical staging for muscle-invasive bladder cancer estimates local and systemic disease burden and can dictate eligibility for systemic therapy and/or radical cystectomy. Herein, we review the accuracy and limitations of current and emerging staging modalities.