Body composition parameter as risk predictor in metastatic renal cell carcinoma (mRCC)?

Abstract

e16506 Background: Imaging-derived data for patient’s (pts) prognostication in advanced/metastatic (m)RCC remains scarce. Recently, imaging body composition parameters such as muscle radiation attenuation (MA) and skeletal muscle index (SMI) as prognostic markers for cancer became a matter of interest. Here, impact of MA and SMI in mRCC pts, treated in our tertiary center, were retrospectively investigated. Methods: During the observation period 01/03 – 05/16, 401 pts mRCC receiving first line medical treatment were identified and analyzed. Pts were included for MA- and SMI-analysis based on Computed tomography (CT) scan data and recorded height and bodyweight, respectively. SMI and MA were assessed by a self-designed software-module using MeVisLab. SMI- and MA-subgroups were established by cutoff points, established using an optimum risk stratification method. Descriptive statistics and overall survival (OS) with Log-rank analysis were administered. Parameters with differences in MA-subgroups (p < 0.2) were analyzed with univariable and multivariable Cox-Regression, once p < 0.2 at each subsequent step. Results: 133 pts were eligible for MA-, 123 pts for SMI-analysis. The median age was 62 (range: 39-84) years, and 65.4% of pts showed an ECOG = 0. 87/133 (65.4%) and 71/123 (57.7%) pts showed low MA and low SMI, respectively. At time of mRCC diagnosis pts with low MA were significantly older (mean: 65 vs. 58 years, p < 0,001), while T-, N-, and M-status, as well as MSKCC did not differ. Low MA was associated with a median OS of 27 (95% CI: 17,1-36.3) mo., compared to 60 (95% CI: 36.7-83.3) mo. for high MA (Log-Rank p = 0.001). Multivariable analysis identified low MA as an independent risk factor for OS (HR 2.07; 95% CI 1.24-3.48; p = 0.006). SMI did not reach significance (p = 0.1) (Tab.1). Conclusions: Here, MA provided a robust prognostic parameter regarding OS in mRCC pts. Interestingly, SMI showed no prognostic impact. CT-derived MA could be a promising addition to existing risk-scores. Further research is needed to validate these finding.[Table: see text]