MP57-16 THE IMPACT OF SURGERY ON THE PROGNOSIS OF METASTATIC RENAL CELL CARCINOMA WITH IVC THROMBUS

Abstract

INTRODUCTION AND OBJECTIVES: Biomarkers may be useful as prognostic indicators prior to and during systemic therapy. We evaluated change in platelet count (DPlt) as a biomarker for response to neoadjuvant tyrosine kinase inhibitor (TKI) therapy for metastatic renal cell carcinoma (mRCC). METHODS: Multi-center retrospective study of mRCC patients undergoing neoadjvant TKI therapy from 5/2005-8/2013. DPlt was defined as post-treatment Plt after first cycle minus pre-treatment Plt. Primary outcome was response of disease to TKI defined by RECIST criteria for partial response (PR), stable disease (SD), and progressive disease (PD). Demographic and clinical characteristics were analyzed between subgroups with stable/increased (+DPlt) and decreased (-DPlt) counts. Cox proportional hazards model evaluated factors associated with changes in tumor response. Kaplan-Meier analysis estimated overall survival (OS) and compared Plt groups with log-rank test. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated for DPlt and disease response PR/SD. RESULTS: A total of 69 patients treated with neoadjuvant TKI therapy were analyzed for DPlt. Overall, 15 patients (22%) were noted to have +DPlt and 54 (78%) had eDPlt after neoadjuvant TKI therapy. There were no other differences in clinical or demographic variables between these two groups (comorbidities, ECOG, tumor size, number of metastases, stage, grade and number of TKI cycles). Patients with +DPlt count had a lower post TKI treatment creatinine (1.0 vs. 1.3, p1⁄40.041). PD was more common among +DPlt 86.7% vs. eDPlt 33.3%, (p1⁄40.001), and SD/PR was more common in eDPlt 66.7% vs. +DPlt 13.3%, (p1⁄40.001). On MVA, -DPlt below baseline was a significant predictor of SD/PR (OR 6.96, p1⁄40.028). A Kaplan Meier analysis (Figure) demonstrated a higher overall survival in -DPlt versus +DPlt (p1⁄40.009), with median survival 13.8 of and 5.7 months respectively. -DPlt had sensitivity of 94.7%, specificity of 41.9%, PPV of 66.7% and NPV of 86.7% for PR/SD after neoadjuvant TKI therapy. CONCLUSIONS: Patients with -DPlt were more likely to respond to TKI therapy and had longer median overall survival. Further investigation is requisite to determine the utility of DPlt as a biomarker for RCC response to TKI.