e17107 Background: Immunotherapy has shown promising clinical responses in patients with metastatic Renal Cell Carcinoma (mRCC) at second-line therapy. Since objective response rates are highly variable, it is utmost important to identify patients who may benefit from immunotherapy to avoid unnecessary adverse effects and costs. Therefore, predictive as well as prognostic markers need to be studied extensively. To our knowledge, none of the body composition measurements such as fat content or skeletal muscle density have been assessed for this purpose. The objective of the current study is to analyze whether skeletal muscle (either muscle mass or muscle density) and adipose tissue play a prognostic role in patients with mRCC who were treated with immunotherapy at second line. Methods: We retrospectively analyzed 14 patients with mRCC who were progressed after tyrosine kinase inhibitor therapy and treated with Nivolumab between March 2016 and September 2019. Skeletal muscle density (SMD), skeletal muscle and adipose tissue were assessed with computed tomography imaging. Overall Survival (OS) and Progression Free Survival (PFS) were estimated by using the Kaplan-Meier method. Results: The median OS was 13,1 months and it was strongly associated with SMD; the median OS was significantly longer in patients with high SMD compared to patients with low SMD (6,9 months vs 18,5 months; P < 0,05). Also in our analysis, SMD separated the intermediate-risk group into 2 groups with different median OS periods, ranging from 8,1 months (95% confidence interval [95% CI], 5,1 months-11,1 months) in patients with intermediate-risk Heng score and low SMD to 21,5 months (95% CI, 14 months-27 months) in patients with an intermediate-risk Heng score and high SMD. Other parameters calculated for adipose tissue or skeletal muscle did not cause any significant change in survival analysis. Conclusions: High SMD appears to be associated with improved outcome in our small patient population. It could be a predictive factor when immunotherapy, Nivolumab, is considered for therapy of mRCC patients at second line.
S&T-52 EARLY CHANGES IN SKELETAL MUSCLE AS A STRONG PROGNOSTIC BIOMARKER IN PATIENTS WITH METASTATIC RENAL CELL CARCINOMA
