OR43: Creatinine to Cystatin C Ratio and BIA for the Assessement of Low Lean Body Mass in Cancer Patient: Comparaison to L3 CT-Scan

Abstract Background Lean body mass (LBM) is an important prognosis factor in cancer patients. Although the L3 CT-scan is considered as a reference method for its assessment, a convenient and easily available method for longitudinal follow-up is required. While bioelectrical impedance analysis (BIA) is widely used its accuracy is discussed; plasma creatinine-to-cystatin C (CC) ratio could be an attractive alternative. The aim of this study was to evaluate CC ratio and BIA ability to detect myopenia in cancer patients compared to the CT-scan use as a standard. Methods Patients with any kind of cancer had body composition evaluation by CT-scan, BIA and CC. Statistical analysis included correlation test, Bland \u0026 Altman and ROC curve analysis. Results Forty-four patients (14 women) were included, 59% of whom had myopenia on CT-scan. Both BIA LBM and CC ratio were well correlated with CT-scan LBM (r = 0.763 and 0.648 respectively) but concordance analysis revealed a 3 kg constant bias towards BIA compared to CT-scan. In terms of ability to detect myopenia, AUC for BIA were 0.675 and 0.388 for men and women respectively. For CC ratio, AUC were 0.813 and 0.673. Conclusion This study shows that LBM assessed by the CC ratio or BIA is well correlated with that determined by L3 CT-scan. The CC ratio capacity to detect myopenia is better to that of BIA. We show that CC ratio can be conveniently used in cancer patient as a reliable biomarker of muscularity.