The Role of Urinary Cytology for Detection of Urothelial Cancer in Asymptomatic Hematuria Investigations

Abstract

Objective: To determine the diagnostic accuracy of urinary cytology to diagnose urothelial cancer for patients with asymptomatic hematuria. Patients and Methods: A retrospective cohort study was undertaken of asymptomatic hematuria patients referred from primary care to the Department of Urology in our institution.  All patients with asymptomatic hematuria received urinary cytology examination. Urinary cytology was classified according to the Paris System.  Patients with visible hematuria (VH) underwent to examine the kidney and bladder with filling using ultrasonography (KBFU), computed tomography urography (CTU) and flexible cystoscopy, while patients with non-visible hematuria (NVH) underwent initially KBFU, and in cases of having risk factors such as smoking history and exposed to chemical substances CTU and flexible cystoscopy were additionally performed.  Results: The study included 790 patients with a median age of 69 years.  Of these patients 235 (29.7%) had VH and 555 (70.3%) were referred for NVH.  In the VH patients 61 (30.0%) and 5 (2.1%) were histologically diagnosed as bladder cancer and upper tract urothelial cancer (UTUC), while in the NVH patients 30 (5.1%) and 2 (0.4%) were histologically identified as bladder cancer and UTUC, respectively.  In the VH group the accuracy of urothelial cancer in the urinary cytology was: sensitivity 24.2% and specificity 100%, while in the NVH group sensitivity 31.2% and specificity 100%.  In histologically confirmed 98 patients with bladder cancer / UTUC the rate of sensitivity in the urinary cytology for even high-grade cancers had only 46.0%.  The rates of sensitivity in any type of hematuria and grade increased by approximately two times with adding atypical cytology results as positive. Conclusion: Although urinary cytology is a convenient and noninvasive test with histologically high specificity for urothelial cancer, the rates of sensitivity of urinary cytology are inferior.  However, adding atypical cytology results as positive improves accuracy of detection of urothelial cancer and prevent from the missing diagnosis.  Nevertheless, urinary cytology has its place as an additive diagnostic tool to cystoscopy and imaging diagnosis for the investigations of asymptomatic hematuria.