Real-World Outcome of 173 Metastatic Non-Clear Cell Renal Cell Carcinoma (nccRCC) Cases: The Experience of the Center Group for Genitourinary Tumors

Abstract

Non-clear cell renal cell carcinoma (nccRCC) represents a group of multiple histologic subtypes, with different clinical outcomes and an uncertain optimal treatment. Data collected in clear cell tumors are routinely extrapolated to nccRCC, despite a different underlying biology. The Center Group for Genitourinary tumors is a network of medical oncologists from hospitals in Madrid and surrounding provinces that are focused on genitourinary tumors. A retrospective, multicenter study of the outcome of patients with nccRCC diagnosed and treated at the Center Group hospitals between 1995 and 2015 was performed. Baseline clinical features, histologic subtypes, therapeutic management and survival status were analyzed. Data was collected from 173 patients, with a median age at diagnosis of 65 years [24-90], 67.1% were male. Histologic subtypes comprised 55.5% papillary carcinoma, 23.1% sarcomatoid, 13.9% chromophobe, 6.9% unclassified tumors and 0.6% oncocytoma. 159 patients received first line therapy including tyrosine kinase inhibitors (67.9%) and mammalian target of rapamycin inhibitors (11.9%). The response rates (RR) in evaluable patients (142) were: complete response 5.6%, partial response 17.6%, stable disease 40.8% and progression in 35.9% of cases. 90 patients (52.0%) received second line treatment. At the time of the data cutoff point (April 1, 2016), 126 patients had died, with a median overall survival (OS) of 17.9 months [95% CI 15.0-20.9]. The clinical outcome reported in this study has a similar OS to other published studies. Nevertheless, there are substantial differences among the distinct subtypes. Overall, prognosis in nccRCC remains poor. No significant differences were observed in the activity of systemic agents, used as either first or second line therapy.