Proteinuria as a Risk Factor for Mortality in Patients with Colorectal Cancer

PURPOSE: We investigated the effects of proteinuria and renal insufficiency on all-cause mortality in patients with colorectal cancer, with special emphasis on cancer staging and cancer-related deaths. MATERIALS AND METHODS: We retrospectively studied a cohort of patients with colorectal cancer. In protocol 1, patients were classified into four groups based on the operability of cancer and proteinuria: group 1, early-stage cancer patients (colorectal cancer stage ≤3) without proteinuria; group 2, early-stage cancer patients with proteinuria; group 3, advanced-stage cancer patients without proteinuria (colorectal cancer stage=4); and group 4, advanced-stage cancer patients with proteinuria. In protocol 2, patients were classified into four similar groups based on cancer staging and renal insufficiency (eGFR <60 mL/min/1.73 m(2)). Between January 1, 1998 and December 31, 2009, 3379 patients were enrolled in this cohort and followed until May 1, 2012 or until death. RESULTS: The number of patients with proteinuria was 495 (14.6%). The prevalence of proteinuria was higher in advanced-stage cancer (n=151, 22.3%) than in early-stage cancer patients (n=344, 12.7%). After adjusting for age, gender and other clinical variables, the proteinuric, early-stage cancer group was shown to be associated with an adjusted hazard ratio of 1.67 and a 95% confidence interval of 1.38-2.01, compared with non-proteinuric early-stage cancer patients. However, renal insufficiency was not associated with colorectal cancer mortality. CONCLUSION: Proteinuria is an important risk factor for cancer mortality, especially in relatively early colorectal cancer.