Prevalence and prognostic significance of proteinuria in patients with lung cancer.

The purpose of the present study was to ascertain the prevalence and prognostic significance of proteinuria in patients with lung cancer. Results of urinary dipstick testing were retrospectively reviewed in 1026 consecutive out-patients with histologically proven primary lung cancer and 475 consecutive out-patients with benign pulmonary disorders. Postoperative urinary dipstick test results were recorded in 243 surgically resected patients. Proteinuria was significantly more frequent in patients with lung cancer than in controls (30.1% vs 8.8%, p < 0.0001). The presence of proteinuria was significantly correlated with advanced disease stage (p < 0.0001). The frequency of proteinuria was significantly higher in patients with small cell carcinoma than in patients with other histologic types (p < 0.01). In the surgically resected patients, preoperative and postresection proteinuria occurred in 25.5% and 10.7% respectively (p < 0.0001). Patients with malignancies and proteinuria had significantly poorer survival than patients with normal urinary protein excretion (p < 0.0001). In a multivariate analysis including TNM stage, histologic type, sex, and age, proteinuria continued to be a significant predictor of reduced survival time. Our results suggest a high prevalence of increased urinary protein excretion in patients with primary lung cancer. Proteinuria may also be an independent predictor of poor survival.