Efficacy of cytoreductive surgery for metastatic upper tract urothelial carcinoma: a Surveillance, Epidemiology and End Results (SEER) study of 508 patients.

Background: Cisplatin-based combination chemotherapy alone is currently considered the standard of care for patients with metastatic upper tract urothelial carcinoma (mUTUC). However, less research has been done on the efficacy of other combinations. In this study, we explored the role of cytoreductive surgery in patients with mUTUC receiving different types of systemic therapy. Methods: Data from 9,436 anonymized records were abstracted from the Surveillance, Epidemiology, and End Results (SEER) database between 2008-2018. Of these, 508 individuals received systemic therapy subsequent to being diagnosed with mUTUC. These patients had all been treated with systemic therapies such as chemotherapy and/or radiotherapy. Patients were stratified into either a non-surgical or surgical group based on cytoreductive surgery status before systemic therapeutics commenced. Kaplan-Meier curves were used to compare overall survival (OS) and cancer-specific survival (CSS). Cox's proportional hazard models were then used to analyze prognostic factors related to OS and CSS. Results: Of the 508 cases, 36.8% (n=187) had received cytoreductive surgery with systemic treatments. The remaining 63.2% (n=321) received either chemotherapy and/or radiotherapy alone. Kaplan-Meier curves showed that 11.6% had 3-year OS [95% confidential interval (CI): 7.1-17.3] for cytoreductive surgery with systemic treatment and 4.9% (95% CI: 2.7-8.0) for systemic treatment alone (P=0.001). The 3-year CSS was 14.9% for cytoreductive surgery plus systemic treatment (95% CI: 9.4-21.7%) and 6.0% (95% CI: 3.4-9.8%) for systemic treatments alone (P=0.003). Under multivariate regression analysis, primary ureter site OS had a hazard ratio (HR) of 0.74 (95% CI: 0.58-0.95, P=0.02) and a CSS HR of 0.72 (95% CI: 0.56-0.94, P=0.01). The cytoreductive surgery OS HR was 0.79 (95% CI: 0.65-0.95, P=0.02) and the CSS HR was 0.75 (95% CI: 0.61-0.92, P=0.006). Additionally, chemotherapy had an OS HR of 0.46 (95% CI: 0.33-0.0.65, P<0.001) and a CSS HR of 0.44 (95% CI: 0.31-0.63, P<0.001). Bones and liver metastases were also indicative of poorer prognosis. Validation was conducted through subgroup analysis which suggested cytoreductive surgery was effective only for patients who received chemotherapy or combined chemo-radiotherapy but not for radiotherapy alone. Conclusions: Cytoreductive surgery provided significantly increased OS and CSS for mUTUC patients who received chemotherapy or combined chemo-radiotherapy in this study. In addition, the primary tumor and metastatic sites were shown to be related to improved patient survival although this was a small and relatively homogeneous cohort of study, sample therefore, further research is required.