Comparison of clinicopathological features in metastatic upper tract urothelial carcinoma and urothelial bladder cancer.

Purpose: To compare the characteristics of primary tumors, sites distribution of metastases and the metastasis-free interval (MFI) between metastatic upper tract urothelial carcinoma (UTUC) and urothelial bladder cancer (UBC), and evaluate the clinicopathological factors associated with MFI.
Methods: We retrospectively reviewed 153 metastatic urothelial carcinoma patients consecutively registered at our hospital from 1997 to 2015, including 71 UTUC and 82 UBC, with a median follow-up of 18.3 months. MFI indicators were assessed by univariate and multivariate logistic regression analysis.
Results: There were significant differences in median age at metastatic disease (p = 0.016), gender (p = 0.018), primary tumor size (p = 0.003), growth pattern (p < 0.001), grade (p < 0.001) and stage (p < 0.001) between metastatic UTUC and UBC. The median MFI of UTUC was dramatically shorter than that of UBC (6.1 vs. 17.4 months, p < 0.001). Univariate analysis revealed pathological stage was the only factor associated with the MFI of UTUC. Multivariate analysis showed that primary tumor grade was an independent inferior predictor for the MFI of UBC (HR 6.384, 95% CI 3.21-12.69, p < 0.001), while recurrence was an independent favorable factor for the MFI of UBC (HR 0.384, 95% CI 0.18-0.82, p = 0.014).
Conclusions: Compared to metastatic UBC, the primary tumors of metastatic UTUC were more invasive and the MFI was significantly shorter. Pathological stage was the only factor associated with the MFI in UTUC, while primary tumor grade and recurrence were independent factors for the MFI of UBC.