AB181. Analysis of clinical and pathological features of mixed epithelial and stromal tumor of the kidney

Objective: To evaluate the clinical significance of lymphovascular invasion (LVI) on recurrence and progression rates in patients with pT1 urothelial carcinoma of bladder after transurethral resection Methods: This retrospective study was performed with 155 patients with newly diagnosed pT1 urothelial carcinoma of bladder who were treated with transurethral resection of bladder tumor (TURBT) at our institution from January 2006 to January 2010. The presence or absence of LVI was examined according to our pathologists. Chi-square was performed to identify the correlations between LVI and other clinical and pathological features. Kaplan-Meier method was used to estimate the recurrence-free survival (RFS) and progression-free survival (PFS) curves and difference was determined by the log-rank test. Univariate and multivariate analyses were performed to determine the predictive factors through a Cox proportional hazards regression model. Results: LVI was detected in a total of 34 patients (21.9%). While LVI was associated with high grade tumors (P<0.001) and intravesical therapy (P=0.009). Correlations with age (P=0.227), gender (P=0.376), tumor size (P=0.969), tumor multiplicity (P=0.196), carcinoma in situ (CIS) (P=0.321) and smoking (P=0.438) were not statistically significant. There was a statistically significant tendency towards higher recurrence rate and shorter RFS time in LVI-positive patients. However, no statistically significant differences were observed in progression rate between the two groups. Moreover, multivariate Cox proportional hazards analysis revealed that LVI, tumor size and smoking were independent prognostic predictors of recurrence. The hazard ratios (95% confidence interval) were 2.042 (1.113– 3.746, P=0.021), 1.817 (1.014–3.256, P=0.045) and 2.079 (1.172–3.687, P=0.012) respectively. Conclusions: The presence of LVI in TURBT specimens is significantly associated with higher recurrence rate and shorter RFS time in patients with newly diagnosed T1 urothelial carcinoma of the bladder. It is an independent prognostic predictor for disease recurrence. Thus, patients with LVI should be followed up closely.