Treatment outcome and survival for patients (pts) with sarcomatoid-variant metastatic renal cell carcinoma (RCC): Memorial Sloan-Kettering Cancer Center (MSKCC) experience

Abstract

e16017 Background: Sarcomatoid-variant represents a spindle cell phenotype of RCC that can be present in any subtype, usually showing aggressive biological behavior. MSKCC experience was studied to provide data on outcome and survival to systemic therapy for metastatic, sarcomatoid-variant RCC. Methods: Clinical features, treatment outcome and survival were reviewed in 63 pts with sarcomatoid-variant metastatic RCC from a database of 650 pts treated at MSKCC with systemic therapy (cytokines, anti-angiogenesis targeted therapy and chemotherapy). Response to therapy, progression-free survival (PFS), and overall survival (OS) was determined for pts based on their first treatment at MSKCC. The percentage of sarcomatoid component in the tumors was assessed. Results: Histology subtypes with sarcomatoid-variant among the 63 pts included 46 clear cell, 5 papillary, 5 chromophobe, 1 collecting duct, and 6 unclassified. 60 pts had prior nephrectomy. MSKCC risk group distribution was 37% good risk, 59% intermediate risk, and 5% poor risk. 34 pts received targeted therapy (29 sunitinib, 3 sorafenib, 2 temsirolimus), 20 pts received cytokine therapy (19 interferon, 1 interleukin) and 9 received other therapies. 5/63 pts achieved an objective response: 1/19 to interferon and 4/29 to sunitinib. In 63 pts, median PFS was 3 months (95% CI 2–4) and median OS was 10 months (95% CI 8–14). Differences in PFS were observed based on therapy (sunitinib vs. all other) and histology (clear cell vs. non-clear cell). The median PFS for sunitinib therapy was 4.4 months (95% CI 2.2–6.7) versus 2 months (95% CI 1.7–2.7) for all other therapies (p = 0.02); and 3 months (95% CI 2.3–4.5) for clear cell versus 1.6 months (95% CI 1.0–2.1) for non-clear cell histology (p = 0.007). In a subset (n = 31) with available specimen, the median % sarcomatoid content was 20% (range 2%-100%). No difference in PFS or OS was observed according to % sarcomatoid content. Conclusions: Metastatic sarcomatoid-variant RCC is associated with a poor prognosis. Sunitinib resulted in a modest response rate and longer PFS versus other therapies. Studies to assess outcome, characterize tumor biology, and develop novel treatment strategies are warranted. [Table: see text]