A rational risk assessment for intravesical recurrence in primary low-grade Ta bladder cancer: A retrospective analysis of 245 cases.

The aim of the present study was to evaluate the prognostic impact of size and number of tumors in primary low-grade (LG) Ta bladder urothelial carcinoma (UC), and thus allow accurate risk stratification of low-risk non-muscle invasive bladder cancer (NMIBC). This study was a retrospective analysis of 245 patients with primary LG Ta UC of the urinary bladder who were treated with transurethral resection. Differences in intravesical recurrence-free survival (RFS) according to various cutoff values of tumor size and tumor number were calculated using Cox proportional hazards model. Median maximum size of tumor was 1.4 cm, and 153 patients (62.4%) had solitary tumors. Forty-nine patients experienced intravesical recurrence during a median 34 months of follow-up. Patients with solitary tumors had significantly longer RFS times compared with those with ≥8 tumors (P=0.003). Patients with larger tumors had significantly shorter RFS times for each cutoff value (P=0.01 for 1.0 cm, P<0.0001 for 1.5 and 2.0 cm, P=0.006 for 3.0 cm). On multivariate analysis, each cutoff value of tumor size was found to be a predictor of RFS; among them, the cutoff of 1.5 cm showed the strongest association (hazard ratio, 4.12; 95% confidence interval, 2.11-8.81; P<0.001). If we consider only lower risk NMIBC patients, such as primary LG Ta, the appropriate cutoff value of tumor size to predict intravesical recurrence might be 1.5 cm, but not 3.0 cm generally adopted in various guidelines. These findings suggest the need for rational risk assessment with consideration of the diversity of patients with NMIBC.