Microalbuminuria in colorectal cancer

Background: Microalbuminuria has been found as a risk factor in many disorders. It is an early marker of diabetic nephropathy. Independent of diabetes, it means an increased risk for atherosclerosis, for cardiovascular diseases and for cardiovascular mortality. It also predicts all-cause mortality. Albuminuria has also been observed in individuals with different locations of cancers. Furthermore, it can be related to the patients' survival, to the efficacy of the treatment and in some cases to the disease extent, too. Aims: We have measured albuminuria by means of two different methodologies (immunoturbidimetry/IT/and high-performance liquid chromatography/HPLC/) to investigate whether elevated albumin-creatinine ratio (ACR) was associated with colorectal cancer (CRC) incidence, with clinical characteristics and with cancer stage. Patients and Methods: A cross-sectional study was carried out on 38 selected patients with CRC and 36 well-matched healthy volunteers, as controls. Urinary albumin excretion was measured by IT and HPLC, and ACR was calculated. Results: Patients with CRC had higher ACR compared to controls using both IT and HPLC (p<0.05). ACR measured by HPLC was higher in both CRC and control groups than ACR measured by IT (p<0.01). In CRC, we found a significant correlation between IT-ACR and red blood cell count (RBC) (r=–0.546; p=0.001), hematocrit (r=–0.389; p=0.030), blood urea nitrogen (r=0.368; p=0.042). We found a significant correlation between HPLC-ACR and RBC (r=–0.456; p=0.009), LDL-cholesterol (r=–0.411; p=0.022), triglyceride (r=–0.524, p=0.002), as well. IT- and HPLC-ACR did not correlate with cancer extent. Stepwise linear regression analysis was carried out in patients with CRC to find predictors of IT- and HPLC-ACR. Independent predictor of IT-ACR was RBC (β=–0.540; p=0.002) and independent predictor of HPLC-ACR was triglyceride (β=–0.466; p=0.014). Conclusions: Urinary ACR is a sensitive marker of CRC and it is not dependent on the cancer extent.