serum cystatin c as a potential marker for glomerular filtration rate in patients with cholangiocarcinoma

Background: cholangiocarcinoma (cca) is the second most common primary hepatobiliary cancer. these patients have meager prognosis and short-term survival. precise assessment of glomerular filtration rate is a fundamental aspect of clinical care in cancer patients. cystatin c has been proposed to be superior to creatinine, a well-known marker of renal function. this study aimed to evaluate cystatin c as a marker of gfr calculation in cca patients.materials and methods: one hundred thirty serum samples from cca patients and 32 from controls were included in this study. serum cystatin c was measured using immunoturbidity assay. estimated glomerular filtration rate was calculated by three equations established by chronic kidney disease epidemiology collaboration (based on creatinine and/or cystatin c).results: serum cystatin c in cca patients was higher than that of controls (p=0.0002). cystatin c was positively correlated with bun in cca group (p=0.019). egfr based on cystatin c and based on both cystatin c and creatinine in cca was low with significantly different from those of control (p<0.001). although there was no difference in egfr using three equations in control, creatinine based egfr was high with significantly different from egfr based on cystatin c and on both creatinine and cystatin c in cca (p=0.000).  proportion in each egfr stage by three equations showed a high sensitivity with significantly different in cca (p<0.05).conclusion: there was a high sensitivity of cys c with significant difference between creatinine and/or cystatin c based egfr in cca patients. it should take account into consideration of mild changes in egfr by cystatin c which is important in managing drug dosage for cca patients.