Clinical outcome and molecular characterization of patients receiving systemic therapy for metastatic sarcomatoid renal cell carcinoma.

Abstract

e15084 Background: Sarcomatoid metastatic renal cell carcinoma (mRCC) represents an aggressive subset of disease, and a definitive therapeutic strategy is lacking. Methods: From an institutional database including 270 patients with mRCC, we identified 34 patients with documented sarcomatoid features. Within this cohort, we assessed 21 patients who received systemic therapy. Survival was assessed in the overall cohort and in subgroups divided by clinicopathologic characteristics, including the extent of sarcomatoid features, MSKCC risk criteria, and the nature of systemic therapy given. Available tissue from 11 of these patients has been identified for correlative studies to assess markers of epithelial to mesenchymal transition (EMT). Tissue will be obtained from a cohort of patients matched for age and MSKCC risk status (but lacking a sarcomatoid component) for comparison. Results: Of the 21 patients assessed, 2 patients received chemotherapy, 7 patients received immunotherapy, and 12 patients received targeted agents as their first line treatment. Median overall survival (OS) in the overall cohort was 18.0 months (95%CI 6.9-22.0). By MSKCC status, patients with poor-risk disease had a median OS of 4.7 months, as compared to 20.1 months for patients with intermediate-risk disease (HR 0.02, 95%CI 0.003-0.15; P=0.0001). Survival in subgroups stratified by the Heng criteria will be presented at the meeting. There was no significant difference in survival in patients with sarcomatoid predominant disease (>20%) vs non-predominant disease (HR 0.62, 95%CI 0.23-1.65; P=0.34), nor was there a difference amongst patients who received targeted therapies vs non-targeted therapies (HR 1.0, 95%CI 0.61-1.40; P=0.36). Correlative analyses are ongoing, and will be presented at the meeting. Conclusions: As compared to previous retrospective series (Golshayan et al JCO 2009) and prospective trials (Haas et al Med Oncol 2011) assessing patients with sarcomatoid mRCC, the survival in our cohort was substantially prolonged. Further clinical and translational studies are needed to refine current prognostic schema for this disease, and to define the optimal therapeutic strategy.