To determine the diagnostic accuracy of urinary cytology to diagnose bladder cancer and upper tract urothelial cancer (UTUC) as well as the outcome of patients with a positive urine cytology and normal haematuria investigations in patients in a multicentre prospective observational study of patients investigated for haematuria.
The DETECT I study (clinicaltrials. gov NCT02676180) recruited patients presenting with haematuria following referral to secondary case at 40 hospitals. All patients had a cystoscopy and upper tract imaging (renal bladder ultrasound [RBUS] and/ or CT urogram [CTU]). Patients where urine cytology were performed were sub-analysed. The reference standard for the diagnosis of bladder cancer and UTUC was histological confirmation of cancer. A positive urine cytology was defined as a urine cytology suspicious for neoplastic cells or atypical cells.
Of the 3556 patients recruited, urine cytology was performed in 567 (15.9%) patients from 9 hospitals. Median time between positive urine cytology and endoscopic tumour resection was 27 (IQR: 21.3-33.8) days. Bladder cancer was diagnosed in 39 (6.9%) patients and UTUC in 8 (1.4%) patients. The accuracy of urinary cytology for the diagnosis of bladder cancer and UTUC was: sensitivity 43.5%, specificity 95.7%, positive predictive value (PPV) 47.6% and negative predictive value (NPV) 94.9%. A total of 21 bladder cancers and 5 UTUC were missed. Bladder cancers missed according to grade and stage were: 4 (19%) were ≥ pT2, 2 (9.5%) were G3 pT1, 10 (47.6%) were G3/2 pTa and 5 (23.8%) were G1 pTa. High risk cancer was confirmed in 8 (38%) patients. There was a marginal improvement in sensitivity (57.7%) for high risk cancers. When urine cytology was combined with imaging, the diagnostic performance improved with CTU (sensitivity 90.2%, specificity 94.9%) superior to RBUS (sensitivity 66.7%, specificity 96.7%). False positive cytology results were confirmed in 22 patients, of which 12 (54.5%) had further invasive tests and 5 (22.7%) had a repeat cytology. No cancer was identified in these patients during follow-up.
Urine cytology will miss a significant number of muscle invasive bladder cancer and high risk disease. Our results suggest that urine cytology should not be routinely performed as part of haematuria investigations. The role of urine cytology in select cases should be considered in the context of the impact of a false positive result leading to further potentially invasive tests conducted under general anaesthesia. This article is protected by copyright. All rights reserved.
BJU international. 2018 Jul 12 [Epub ahead of print]
Wei Shen Tan, Rachael Sarpong, Pramit Khetrapal, Simon Rodney, Hugh Mostafid, Joanne Cresswell, Dawn Watson, Abhay Rane, James Hicks, Giles Hellawell, Melissa Davies, Shalom J Srirangam, Louise Dawson, David Payne, Norman Williams, Chris Brew-Graves, Andrew Feber, John D Kelly, DETECT I trial collaborators
Division of Surgery and Interventional Science, University College London, London, UK., Surgical & Interventional Trials Unit, University College London, London, UK., Department of Urology, Royal Surrey County Hospital, Guildford, UK., Department of Urology, James Cook University Hospital, Middlesbrough, UK., Department of Urology, East Surrey Hospital, Redhill, UK., Department of Urology, Worthing Hospital, UK., Department of Urology, Northwick Park Hospital, London, UK., Department of Urology, Salisbury District Hospital, Salisbury, UK., Department of Urology, East Lancashire Hospital, Blackburn, UK., Department of Urology, Royal Bolton Hospital, Bolton, UK., Department of Urology, Kettering General Hospital, Kettering, UK.