Evaluation of the diagnostic accuracy of UBC® Rapid in bladder cancer: a Swedish multicentre study

Objective: The aim of this study was to determine the diagnostic accuracy of UBC (R) Rapid - a urine-based marker for bladder cancer - in patients with bladder cancer and controls, and to compare the test results across risk groups. Materials and methods: This prospective phase II study was conducted at four Swedish hospitals. UBC Rapid was evaluated in four groups: A, newly diagnosed bladder cancer (n=94); B, follow-up of non-muscle-invasive bladder cancer (n=75); C, benign urinary tract diseases (n=51); and D, healthy controls (n=50). Tumours were divided into high risk (carcinoma in situ, TaG3, T1, T2 and T3) and low risk (low malignant potential, TaG1 and TaG2). Urine samples were quantitatively analysed by UBC Rapid. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated based on optimal cut-off (receiver operator characteristics curve analysis). A linear regression compared the UBC Rapid results in the different risk groups. Results: The optimal cut-off was 8.1g/l. The median UBC Rapid values were 9.3g/l [interquartile range (IQR) 30.9] and 4.3g/l (IQR 7.8) in patients with positive and negative cystoscopy, respectively (p<.001). The value for group A was 15.6g/l (IQR 37.9), group B 5.6g/l (IQR 8.6), group C 5.1g/l (IQR 9.0) and group D 3.3g/l (IQR 7.1). Sensitivity was 70.8%, specificity 61.4%, PPV 71.3% and NPV 60.8%. The high-risk group had significantly higher UBC Rapid values than the low-risk group: 20.5g/l (IQR 42.2), sensitivity 79.2% and specificity 61.4% versus 7.0g/l (IQR 9.9), sensitivity 60.0% and specificity 61.4% (p=.039). Conclusions: The UBC Rapid urine-based marker for bladder cancer gave higher values in patients with positive than in those with negative cystoscopy. The diagnostic accuracy was better in patients with high-risk than in those with low-risk tumours, and was better during primary detection than during surveillance.