STOCKHOLM, SWEDEN (UroToday.com) - In this session, Dr. B.W.G. Van Rhijn presented a state-of-the-art lecture on the use of urinary markers in patients with bladder cancer.
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The importance of tumor incidence on efficacy of diagnostic testing was reviewed. Tumor incidence can greatly affect the positive (PPV) and negative (NPV) predictive value of a test. For example, the PPV and NPV for a tumor with an incidence of 40% is 75% and 83%, respectively, while for a tumor with an incidence of 4% is 16% and 99%, respectively. Therefore, when considering a new diagnostic or screening test, sensitivity and specificity should be used in place of predictive value.
While urinary cytology and cystoscopy are extensively used in the diagnosis and management of bladder cancer, the former has a low sensitivity while the later is invasive and can be expensive. The EAU guidelines recommend urinary cytology for patients with high-grade urothelial carcinoma and for primary detection and follow-up. Urine markers (UM) are not yet fully established, but a number are currently in use, including ImmunoCyt, BTA, FISH, and microsatellite analysis. Patient selection is the most important consideration in the choice of a UM, and can be divided into screening and primary bladder cancer follow-up of high-risk (G3/CIS) and intermediate-/low-risk disease. The primary aim of UM-targeted screening is detection of G3 disease prior to muscle invasion. However, widespread screening for non-muscle invasive bladder cancer (NMIBC) is unlikely to be useful given the relatively low incidence of bladder cancer and the relatively short lead-time.
Dr. Van Rhijn then reviewed the results from a randomized controlled trial of microsatellite UM screening among men with NMIBC. The study was performed among 10 institutes in the Netherlands, and included 448 patients with low-/intermediate-risk bladder cancer. Patients with T2 or greater or CIS/G3 disease were randomized to standard screening for 2 years (control) or standard screening, plus urine microsatellite analysis. In the intervention arm, an abnormal microsatellite analysis prompted cystoscopy. Sensitivity and specificity of the urine microsatellite analysis were 58% and 73%, respectively. Interestingly, more recurrences were diagnosed in the intervention arm compared to the control arm (32% versus 5%). Since the results of microsatellite analysis were reported to the urologists, cystoscopy was likely performed with an increased index of suspicion, which led to the diagnosis of more tumors. This also increased the sensitivity of microsatellite analysis to 70% from 58% (versus only 24% in control arm).
In conclusion, the sensitivity and specificity of microsatellite analysis to detect NMIBC among patients with low- to intermediate-risk disease is low. However, knowledge of a positive urine microsatellite analysis results in a more thorough and careful cystoscopic bladder assessment. The sensitivity of microsatellite analysis is highly influenced by the quality of cystoscopy, and can lead to increased tumor detection.
Presented by B.W.G. Van Rhijn at the 29th Annual European Association of Urology (EAU) Congress - April 11 - 15, 2014 - Stockholmsmässan - Stockholm, Sweden.
Amsterdam, The Netherlands
Written by Jeffrey J. Tomaszewski, MD, medical writer for UroToday.com