Microalbuminuria in patients with lung cancer.

In a prospective study of 102 outpatients with histologically proven lung cancer, the prevalence and prognostic significance of microalbuminuria (urinary albumin excretion > 20 micrograms/min) were analysed. 65 consecutive outpatients with benign lung disorders served as controls. An immunoturbidimetric assay, sensitive at low concentrations, was used to quantify the albumin excretion rate in timed overnight urine samples. Patients with malignancies had a significantly higher frequency of microalbuminuria (32.4% compared with controls, 13.8%, P < 0.01) and median urinary albumin excretion rate (13.4 versus controls, 8.9 micrograms/min, P < 0.003). Urinary albumin excretion was significantly higher in lung cancer patients with TNM stage III and IV. Patients with malignancies and microalbuminuria had a significantly lower survival rate than patients with normoalbuminuria (probability of survival 1 and 3 years after diagnosis 66% and 16% versus controls, 22% and 4%, P < 0.00001). In a multivariate model, which adjusted for age, sex, performance status, histological type and TNM stage, microalbuminuria continued to be a significant predictor of survival. In conclusion, an increased prevalence of microalbuminuria has been demonstrated in patients with lung cancer. The presence of microalbuminuria was associated with advanced disease stage and poor survival.