Impact of Squamous and Glandular Differentiation on Oncologic Outcomes in Upper and Lower Tract Urothelial Carcinoma

PURPOSE: To investigate the prognostic significance of squamous and/or glandular differentiation in urothelial carcinoma (UC). MATERIALS AND METHODS: Among 800 consecutive patients who underwent radical cystectomy or nephroureterectomy at our institution from January 1990 to December 2010, 696 patients were included for the analysis. Clinicopathologic variables were compared according to the presence of squamous and/or glandular differentiation and the tumor location. RESULTS: A total of 51 (7.3%) patients had squamous and/or glandular differentiation. Patients with squamous and/or glandular differentiation had higher pathological T stage (p<0.001) and grade (p<0.001) than those with pure form of UC. After the median follow-up of 55.2 months, 84 (24.6%) and 82 (23.1%) died of upper urinary tract UC and UC of bladder, respectively. Patients with squamous and/or glandular differentiation in upper urinary tract UC showed poorer cancer-specific survival (CSS) (p<0.001) and overall survival (OS) (p<0.001) than those with pure form in upper urinary tract UC (p<0.001), but not in UC of bladder (p = 0.178 for CSS and p = 0.172 for OS). On multivariate Cox regression analysis, squamous and/or glandular differentiation was an independent predictor of CSS (hazard ratio [HR] 1.76; 95% confidence interval [CI] 1.08–2.85, p = 0.023), but it was not associated with OS (HR 1.52; 95% CI 1.00–2.32, p = 0.051). CONCLUSIONS: The presence of variant histology could be associated with poorer survival outcome in patients with UC. Squamous and/or glandular differentiation is associated with features of biologically aggressive disease and an independent predictor of CSS.