Does the presence of muscularis propria on transurethral resection of bladder tumour specimens affect the rate of upstaging in cT1 bladder cancer?

Abstract

OBJECTIVE • To determine how the presence of MP on T1 biopsy specimens affects the outcome of patients undergoing RC as compared to when no MP is identified in the TURBT specimen. • Patients were retrospectively identified from the Columbia University Urologic Oncology Database. • From January 1986 to October 2009, 114 patients diagnosed with cT1N0M0 bladder cancer who underwent RC within 4 months of their last biopsy were identified. • Patients were stratified based on the presence of MP on T1 biopsy, and upstaging was defined as any tumor T2 or greater, N+, or M+ at the time of radical cystectomy. • The rate of upstaging was assessed using univariate and multivariate regression models; Kaplan meier curves were also extrapolated for each cohort to compare disease specific and overall survival patterns. • Of the 114 patients evaluated in this study, 24 (20.2%) did not have MP on their T1 biopsy before RC. The rate of upstaging (>=pT2) stratified by the presence of MP on biopsy was 50% and 78%, respectively (p = 0.017). • On univariate analysis, lack of MP on biopsy was associated with an increased risk of upstaging (HR 3.52, p = 0.021, CI 1.2-10.3), however did not reach significance as an independent predictor (HR 2.9, p = 0.056, CI 0.97-8.9). • At a mean follow-up of 33.5 months, there was no difference in disease specific (p = 0.41) and overall survival (p = 0.68) between groups. • The lack of MP on TURBT for high grade cT1N0M0 bladder cancer portends a high likelihood of upstaging at RC, although this risk did not translate into a detectable increased risk of disease specific mortality.