Occurrence and prognostic significance of different histology relative to urinary tract tumors: A SEER population-based study.

Abstract

485 Background: To evaluate the prevalence and prognostic value of variant histology in urinary tract tumors according to primary location and metastatic status. Methods: Using the Surveillance, Epidemiology, and End Results registry (SEER, 2004-2015) databases, patients with urinary tract tumors were identified. Propensity Score Matching was used to balance the clinicopathologic features between different histologies. Kaplan-Meier plots were used to compare the cancer specific survival (CSS) and overall survival (OS) of different histologies. The cox regression analysis were also applied. Results: Of all 93,200 eligible patients with urinary tract tumors, 87,323 (93.7%) harbored bladder cancer (3,685 in M1 stage). Among them, urothelial tumors (UC) accounted for 96.67%, followed by squamous neoplasm (SCC), urachal carcinoma (Urachal), adenocarcinoma (Adeno), neuroendocrine tumors (NE) and tumor of Müllerian type (Müllerian). A total of 5877 (6.35%) harbored upper urinary tract tumors (950 in M1 stage). Among them, UC accounted for 96.39%, followed by SCC, Urachal, Müllerian, NE, Adeno. In patients with localized diseases, those with non-urothelial tumors had significantly worse prognosis in overall urinary tract tumors based on OS and CSS (P<0.001). In terms of specific histology in bladder cancer (BC), patients with UC had most favorable prognosis, followed by Adeno, Urachal and Müllerian, while those with SCC and NE were associated with the worst survival outcomes. In patients with upper urinary tract tumors (UUTT), those with Müllerian had the best survival outcomes, followed by UC, while those with NE, Adeno, SCC, and Urachal had relatively worse prognosis. In M1 stage, although there was a statistical difference in OS and CSS between all patients with urothelial and non-urothelial tumors (P<0.001), the 5-year survival rate (3.74%, 2.50%) and 5-year CSM (4.93%, 3.28%) were similar. In metastatic BC, there was no difference in OS among all histology. However, in terms of CSS, significant differences were still observed in patients with different histologies. In metastatic UUTT, no difference in survival was found among different histologies. After PSM, the similar results were observed in BC, while there is no statistical difference of survival among different histologies in UUTT, no matter the M stage. Cox analyses revealed that primary location, histology type, surgery, chemotherapy and M stage were the common and strong independent prognostic factors in both BC and UUTT. Conclusions: In urinary tract tumors, the incidence of different histology types between BC and UUTT is roughly similar. Overall, patient with variant histology have a worse prognosis than those with urothelial carcinoma. However, differences in survival among the histology types vary by primary location and metastatic status, especially the metastatic status.