Clinical outcomes and survival of patients (pts) with sarcomatoid metastatic renal cell carcinoma (smRCC).

Abstract

535 Background: SmRCC is a rare variant of RCC associated with poor outcome. No definitive therapeutic recommendations exist. We present survival outcomes in pts with smRCC treated with systemic therapy. Methods: From a single institutional database (years 2000-2012), we identified 21 pts with documented sarcomatoid features who received systemic therapy. Survival was assessed in the overall cohort and in subgroups divided by clinicopathologic characteristics, including the extent of sarcomatoid features, and Memorial Sloan-Kettering Cancer Center (MSKCC) risk criteria. Sarcomatoid component of the tumor was classified by predominant (≥20%) and non-predominant (<20%). Immunohistochemistry (IHC) analysis was performed for mammalian target of rapamycin (mTOR) signaling, phosphorylated ribosomal protein S6, proviral integration site proteins (PIM 1,2,3), Beta-catenin, E-cadherin, phosphatase and tensin homolog (PTEN), U3 small nucleolar ribonucleoprotein (IMP-3), p53, and epithelial membrane antigen (EMA) on tumor samples, where available. Results: 21 pts were included with a median age of 62 years (range 39-74) and 13 pts were male (62%). One pt received first line cytotoxic chemotherapy, 3 pts received first line immunotherapy, and 17 pts received targeted therapy. Pts belonged to the following MSKCC risk categories: 1 (5%) favorable, 13 (62%) intermediate and 7 (33%) poor risk. Median overall survival (OS) of the entire cohort was 249 days (95% CI 161-519 days). Median OS in pts stratified as MSKCC poor, intermediate, and good risk was 2556, 430, and 137 days respectively (Poor vs Intermediate HR 4.38, p = 0.0159, CI 1.30-19.90). There was no significant difference in OS in pts with sarcomatoid predominant disease vs. non-predominant disease (234 vs 286 days, p = 0.744, HR 0.85, CI 0.31-2.39). Conclusions: Overall OS in pts with smRCC is inferior compared to that reported in clear cell variant mRCC. Although MSKCC risk scores may be useful in determining prognosis, further studies are needed to identify relevant biomarkers and define the optimal therapeutic strategy for this disease. Correlation of survival outcomes with the IHC profile of tumors will be presented.