Muscle-invasive bladder cancer developing after nephroureterectomy for upper urinary tract urothelial carcinoma

Objectives: To evaluate the risk factors and prognosis of muscle-invasive bladder cancer (MIBC) developing after nephroureterectomy for upper urinary tract urothelial cell carcinoma (UUT-UC). Materials and methods: We reviewed the medical records of 422 patients who underwent nephroureterectomy for UUT-UC between 1990 and 2010, and identified 173 (40.9%) with intravesical recurrence and 28 (6.6%) with MIBC. We evaluated the clinicopathologic features, risk factors, and cancer-specific survival (CSS) using the Kaplan-Meier method and the Cox proportional hazards regression models. Results: The median intervals from nephroureterectomy to intravesical recurrence and the development of MIBC were 8 and 17 months, respectively. On multivariate analysis, the pathologic stage (≥pT3 vs. Ta/T1, HR 5.03, P = 0.001) and ureteral tumor location (HR 2.79, P = 0.011) were independent risk factors for the development of MIBC, whereas a history of previous or concomitant bladder tumor was the only significant risk factor for intravesical recurrence. The probability of developing MIBC 5 years after nephroureterectomy was 12.6% in patients with 1 risk factor and 20.6% in patients with both risk factors. Patients with MIBC had significantly worse CSS than those without MIBC (P = 0.004), whereas CSS rates were similar in patients with and without intravesical recurrence (P = 0.593). However, stratification analysis for matching pathology revealed that CSS rates were not significantly different in patients with pT2 or higher stage of UUT-UC. Conclusions: Approximately 5% of the patients developed MIBC after nephroureterectomy with a median interval of 17 months. Patients with advanced pathologic stage (≥pT3) and a ureteral tumor location are at increased risk of developing MIBC after nephroureterectomy.