Monitoring of renal function in cancer patients: an ongoing challenge for clinical practice.

BACKGROUND Renal impairment (RI) has been shown to be one major risk factor in a number of diseases and is associated with a dismal clinical outcome. However, the influence of milder degrees of renal disease is less well defined, particularly not in patients with malignant diseases. PATIENTS AND METHODS We analyzed 167 patients with solid tumors and hematological malignancies. Besides disease-specific parameters, serum creatinine, cystatin C and the estimated glomerular filtration rate (eGFR) ['modification of diet in renal disease' equation (MDRD)/Cockcroft-Gault (CG)] were determined. Patients were compared within eGFR, creatinine and cystatin C groups. RESULTS The median MDRD, CG, creatinine and cystatin C levels of all patients were 88 ml/min/1.73 m2, 89 ml/min, 1 mg/dl and 0.9 mg/l, respectively. Patients with chronic kidney disease stage 2 still showed normal creatinine and cystatin levels of 1 mg/dl and 1.1 mg/l, respectively, although mild RI was frequent. Those cancer patients with decreased eGFR (MDRD) (<60 ml/min/1.73 m2) had increased odds ratios (ORs) to have more concurrent diagnoses [OR 3.4; 95% confidence interval (CI) 1.5-8.1], a body mass index >24 kg/m2 (OR 2.1; 95% CI 1.0-4.5) and an elevated (> 245 pg/ml) pro-brain natriuretic peptide level (proBNP) (OR 9.2; 95% CI 3.0-28.3). CONCLUSIONS These observations suggest that grouping cancer patients according to renal function, especially eGFR, may be one way to determine specific risk groups.