Impact of treatment modalities on prognosis of patients with metastatic renal collecting duct carcinoma.

Although patients with renal collecting duct carcinoma (CDC) benefit from surgery, the value of cytoreductive nephrectomy (CNx) for the prognosis of patients with metastatic CDC remains unclear. Hence, in this study, we used data from Surveillance, Epidemiology, and End Results (SEER) registry to investigate the prognostic factors and the impact of CNx on the outcomes in patients with metastatic CDC. Data of 521 patients, diagnosed with CDC between 2000 and 2018, were retrieved from the SEER database. Kaplan-Meier method and log-rank tests were used to compare the survival differences between the CNx group and non-surgical group. Multivariate Cox regression analysis was used to identify the risk factors associated with overall survival (OS) and cancer-specific survival (CSS) for patients with metastatic CDC. Moreover, multivariate Cox regression analysis guided by directed acyclic graphs (DAG) was used to unfold the impact of CNx and chemotherapy on OS and CSS. 86 patients were identified to have metastatic CDC. The median OS and CSS time were 5 and 6 months, respectively. The OS rates at 1-, 2- and 5-years were 24.4%, 15.1% and 2.3%, respectively. Whereas, the CSS rates at 1-, 2- and 5-years were 27.0%, 17.9% and 2.8%, respectively. Old patients and those receiving CNx or chemotherapy exhibited better survival outcomes. The multivariate regression model identified non-surgical treatment as the only independent prognostic factor for both, OS and CSS. However, DAG-guided multivariate Cox regression model showed that both, CNx and chemotherapy, were associated with both, OS and CSS. Patients with metastatic CDC exhibited worse clinical outcomes. However, CNx improved the prognosis of patients with metastatic CDC. Additionally, surgical resection of visible lesions and suitable chemotherapy were identified as alternative treatment strategies.