Proteinuria: a frequent paraneoplastic phenomenon in colorectal cancer?

Cancer risk in patients with diabetic nephropathy: A retrospective cohort study in Hong Kong

Diabetic nephropathy (DN) is a leading cause of end-stage kidney disease nowadays. Certain cancers are more common in patients with diabetes mellitus. However, there are no data concerning the cancer pattern in patients with DN. The aim of this study is to investigate the site-specific cancer risk and mortality in these patients.A retrospective cohort study of 5643 DN patients between 2000 and 2015 was conducted in 2 large hospitals in Hong Kong. Incidence and mortality of various cancers were compared with those of general population using standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) respectively.With 24,726 person-years follow-up, 250 cancers were diagnosed. Overall cancer incidence was similar between DN patients and the general population (SIR 1.05, 95% confidence interval [CI] 0.92-1.19). However, certain site-specific cancers are increased in DN patients: the highest risk was observed for laryngeal cancer (SIR 3.03, 95% CI 1.11-6.60), followed by cancers of liver (SIR 1.96, 95% CI 1.35-2.76) and colorectum (SIR 1.92, 95% CI 1.53-2.37), but the risk of prostate cancer was lower (SIR 0.48, 95% CI 0.21-0.95) in the males with DN. The SMR of all cancers was 1.17 (95% CI 1.01-1.37). For individual specific site, only colorectal cancer carried a significant higher mortality risk (SMR 2.45, 95% CI 1.82-3.23).Our data suggested that DN is associated with increased incidence of cancers of colorectum, liver, and larynx but decreased incidence of prostate cancer. Moreover, there is increased mortality of colorectal cancer in patients with DN.

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.

Association of albuminuria and cancer incidence

Albuminuria, which is associated with noncardiovascular mortality, might be a result of altered vascular permeability caused by cytokines and other tumor cell products. The aim of this population-based, longitudinal study was to examine whether elevated albumin-to-creatinine ratio (ACR) is associated with cancer incidence. A total of 5425 participants without diabetes or previous cancer in the Tromsø Study were followed; 590 had a first diagnosis of cancer during 10.3 yr of follow-up. The ACR at baseline significantly correlated with the incidence of cancer, even after adjustment for age, gender, body mass index, physical activity, and smoking (P < 0.001). Participants with ACR in the highest quintile were 8.3- and 2.4-fold more likely to receive a diagnosis of bladder cancer and lung cancer, respectively, compared with those with ACR in the lowest quintile after similar adjustments. It is concluded that albuminuria is associated with cancer incidence in individuals without a history of diabetes, macroalbuminuria, or previous cancer and that it might confer risks of varying magnitude for different types of cancer.

Increased urinary albumin excretion rate in breast cancer patients

A high frequency of slightly increased urinary albumin excretion (UAE) has been reported in patients with malignancies. Earlier studies have indicated a prognostic significance of UAE in some malignant diseases. We measured urinary albumin in 24-h urine samples in 44 patients with newly diagnosed early breast cancer and in 22 patients with relapse of metastatic breast cancer disease. The prevalence of microalbuminuria ( > or = 20 microg/min) was 20.5% in patients with early breast cancer and 54.5% in patients with metastatic disease. Median UAE was significantly higher in patients with metastatic breast cancer compared with the early breast cancer group (20.5 microg/min vs. 9.2 microg/min; p < 0.01). In patients with metastatic breast cancer, univariate survival analysis revealed a significantly lower survival rate in patients with microalbuminuria compared with the normoalbuminuric group (p <0.001). The present study demonstrates a high frequency of microalbuminuria in patients with breast cancer. Increased UAE was most prevalent in patients with metastatic disease. Our results also suggest that UAE may be a prognostic marker in metastatic breast cancer. Further prospective studies with a larger number of patients and controls are needed to test the validity of these observations.

Urinary albumin excretion and transcapillary escape rate of albumin in malignancies

Transcapillary escape rate of albumin was determined in 22 patients with different malignancies. In addition, urinary albumin excretion rate was measured in 24-h urine samples using a sensitive immunoassay. Increased urinary albumin excretion was defined as >/=20 microg/min according to conventional standards. Renal glomerular filtration and tubular function was estimated by 51Cr-EDTA plasma clearance and urinary beta 2-microglobulin, respectively. Median urinary albumin excretion rate was 15.0 microg/min (range 6-510 microg/min) and the frequency of increased urinary albumin excretion was 41%. This agrees with other studies showing increased albuminuria in several types of malignant diseases. Patients with advanced disease (tumour, node, metastasis (TNM) stage II-IV) had a significantly higher urinary albumin excretion rate than patients with localized disease (TNM stage I). Serum creatinine, glomerular filtration rate and urinary beta 2-microglobulin were all within normal limits. Median transcapillary escape rate of albumin was 5.5 %/h (range 2-8 %/h) and this level is comparable with values in healthy subjects. There was no significant difference in transcapillary escape rate between patients with elevated urinary albumin excretion and the normoalbuminuric group. Median value of the absolut outflux of albumin was 10.6 g/h with similar levels in patients with increased urinary albumin excretion and patients with normoalbuminuria. Our results indicate a high prevalence of minor glomerular dysfunction with a slightly elevated urinary albumin excretion in patients with malignancies. The normal endothelial function, as estimated by the transcapillary escape rate of albumin, suggests an overall unaffected capillary permeability and increased urinary albumin loss appears to be an isolated renal phenomenon in cancer patients.

Clinical significance of urinary albumin excretion in patients with non-Hodgkin's lymphoma

Slightly increased urinary albumin excretion rates (UAE) have been reported in patients with various types of human cancer. We measured UAE in 24 h urine samples from 48 untreated patients with non-Hodgkin's lymphoma at diagnosis. In patients with a pretreatment UAE >/=20 microgram/min, post-treatment value of UAE was determined following completion of the last treatment. The median UAE was 15.0 microgram/min and the prevalence of microalbuminuria (UAE >/=20 microgram/min) was 39.6%. Increased UAE was significantly associated with Ann Arbor stage, performance status, serum lactate dehydrogenase (LDH) level, and the International Prognostic Index (IPI). The median posttreatment value of UAE was significantly lower than the pretreatment value (P < 0.0001). Our data suggest a clinical and prognostic significance of UAE in patients with non-Hodgkin's lymphoma.