Urinary collecting system invasion is associated with poor survival in patients with clear-cell renal cell carcinoma

Objectives: To evaluate the prognostic significance of urinary collecting system invasion (UCSI) in a large series of patients with clear-cell renal cell carcinoma (RCC). Materials and Methods: Patients with clear-cell RCC treated with nephrectomy between 2001 and 2010 were reviewed from a prospectively maintained registry. One urological pathologist re-reviewed all slides. Cancer-specific survival was estimated using the Kaplan–Meier method, and associations of UCSI with death from RCC were evaluated using Cox models. Results: Of the 859 patients with clear-cell RCC, 58 (6.8%) had UCSI. At last follow-up, 310 patients had died from RCC at a median of 1.8 years after surgery. The median follow-up for patients alive at last follow-up was 8.2 years. The estimated cancer-specific survival at 10 years after surgery for patients with UCSI was 17%, compared with 60% for patients without UCSI (P < 0.001). In a multivariable model, UCSI remained independently associated with an increased risk of death from RCC (hazard ratio 1.5; P = 0.018). Further, among patients with pT3 RCC, those with USCI had survival outcomes similar to those of patients with pT4 RCC. Conclusions: Collecting system invasion is associated with poor prognosis among patients with clear-cell RCC. If validated, consideration should be given to including UCSI in future staging systems.