The Efficacy of Serum Cystatin C and Creatinine to Diagnose Impaired Renal Function in Cancer Patients Under Treatment with Cisplatin

Renal function can be impaired in cancer patients treated with cisplatin. Currently, serum creatinine is used to diagnose renal dysfunction. This study aims to determine the efficacy of serum cyatatin C and ceratinine in contrast to the 24-hour urine creatinine clearance [CrCl] as the gold standard method in diagnosis of renal dysfunction in cancer patients under treatment with cisplatin. Seventy patients under treatment with cisplatin included. Serum cystatin C and creatinine were measured. CrCl in 24-hour urine was calculated. Measurements were done two times; before initiation of chemotherapy and before the fourth cycle of the chemotherapy. Then, using Receive Operating Curve [ROC] curve and at different cut-off points, sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV] of both cystatin C and creatinine to detect renal dysfunction were calculated. 24-hour urine CrCl was the gold standard method to define renal dysfunction. Sensitivity and specificity values of cystatin C of > 1.28 mg/L to predict CrCl < 78 mL/min were 77% and 95%, respectively. PPV and NPV of cystatin C were 95% and 79%, respectively with a diagnostic accuracy of 86%. On the other hand, sensitivity and specificity of creatinine were 64% and 47%, respectively. Serum cystatin C concentration had better sensitivity, specificity, PPV, and NPV compared to creatinine in detection of early stages of renal dysfunction in cancer patients under treatment with cisplatin. This marker can be used as an effective screening method in such patients to find renal dysfunction at its early stages.