URINARY BETA-GLUCURONIDASE ACTIVITY AS AN INITIAL SCREENING-TEST FOR URINARY-TRACT MALIGNANCY IN HIGH-RISK PATIENTS - COMPARISON WITH CONVENTIONAL URINE CYTOLOGIC EVALUATION

Background. Routine urine cytology is not particularly useful as a scr eening test for urinary tract malignancy in the general population, du e to its low detection rate. Bladder, ureteral, and pelvic lavage and flow cytometry increased the test sensitivity but could be applied onl y to a limited number of patients. A simple, sensitive screening test is needed. Methods. Two hundred eighty-two urine samples from 146 pati ents from the Urology Tumor Clinic patients during their initial visit s were subject to cytologic evaluation and measurement of the activity of endogenous beta-glucuronidase, followed by confirmation procedures , including cystoscopy with biopsy, ultrasonography, radiography and/o r computed tomography. Results. Among 146 patients, 32 had confirmed t ransitional cell carcinoma and 14 renal cell carcinoma. The urinary be ta-glucuronidase activity was higher in patients with cancer than in t hose without cancer in the Urology Service and in 80 normal healthy co ntrol subjects. The accuracy of the urine enzyme diagnostic system mea sured by the receiver-operating characteristic (ROC) plot was 98% or h igher based on the number of patients. The upper threshold value deter mined by ROC analysis was 1.7 nmol/min/mu mol creatinine. At this thre shold value, the sensitivities of the enzyme assay for transitional ce ll carcinoma, renal cell carcinoma, and all cancers were, respectively , 94%, 98%, and 95%. These values were much higher than the correspond ing sensitivities of urine cytology: 41%, 0%, and 22%. Conclusion. Uri nary beta-glucuronidase is a much more sensitive test to screen for ur inary tract malignancy than routine urine cytology in high risk patien ts, provided that a positive test is followed by diagnostic procedures for confirmation.