Impact of tumor size on the oncological outcome of high-grade nonmuscle invasive bladder cancer - examining the utility of classifying Ta bladder cancer based on size

PURPOSE: To examine survival rates and to calculate the risk of disease recurrence, progression, overall, and cancer-specific mortality in patients diagnosed with high-risk NMIBC using a multi-institutional dataset to evaluate differences between the guidelines of the European Association of Urology and the guidelines of the National Comprehensive Cancer Network (NCCN) with regard to tumor size in risk stratification.

METHODS AND MATERIAL: In total 1,116 individuals diagnosed with high-risk NMIBC between 2001 and 2013 were included in the analysis. Patients were stratified to NCCN guideline recommendations (high-grade T1, high-grade Ta ≤ 3 cm, and high-grade Ta > 3 cm). Recurrence and progression rates were calculated. Kaplan-Meier curves were fitted to examine differences in recurrence-free (RFS) and progression-free survival (PFS). Multivariable Cox proportional hazards regression models were employed to calculate differences in the RFS, PFS, overall, and cancer-specific survival (CSS).

RESULTS: The majority of patients were diagnosed with high-grade T1 disease (N = 576, 51.6%), while 34.2% and 14.2% of patients were diagnosed with high-grade Ta ≤ 3 cm and Ta > 3 cm NMIBC, respectively. The 1- and 5-year RFS (1-year: 80.5% vs. 64.9%; 5-year: 58.6% vs. 48.3%, P = 0.048) and PFS (1-year: 99.1% vs. 98.6%; 5-year: 97.7% vs. 92.4%, P = 0.054) rates were higher in patients with Ta ≤ 3 cm. Patients diagnosed with high-grade Ta > 3 cm experienced unfavorable progression-free, and cancer-specific survival compared to high-grade Ta ≤ 3 cm, respectively (PFS: 2.41, 95% confidence interval [CI] 1.05-5.56, P = 0.038; CSS: hazard ratios [HR] 2.22, 95% CI 1.02-4.89, P = 0.048).

CONCLUSION: Patients diagnosed with high-grade Ta NMIBC ≤3 cm demonstrated a favorable progression-free, and cancer-specific survival compared to patients diagnosed with high-grade Ta > 3 cm and high-grade T1 NMIBC.