AUTHOR=Chai C. A. , Yeoh W. S. , Rajandram R. , Aung K. P. , Ong T. A. , Kuppusamy S. , Nazran A. , Kumaran K. , Razack A. H. A. , Teoh J. Y. 

TITLE=Comparing CxBladder to Urine Cytology as Adjunct to Cystoscopy in Surveillance of Non-muscle Invasive Bladder Cancer—A Pilot Study

JOURNAL=Frontiers in Surgery

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/surgery/articles/10.3389/fsurg.2021.659292

DOI=10.3389/fsurg.2021.659292

ISSN=2296-875X

ABSTRACT=Purpose: Guidelines advocate cystoscopy surveillance(CS) for non-muscle invasive bladder cancer(NMIBC) post-resection. However, cystoscopy is operator dependent and may miss upper tract lesions or carcinoma in-situ(CIS). Urine cytology is a common adjunct but lacks sensitivity and specificity in detecting recurrence. A new mRNA biomarker (CxBladder) was compared with urine cytology as an adjunct to cystoscopy in detecting a positive cystoscopy findings during  surveillance cystoscopy in our center.

Materials and methods: Consented patients older than 18, undergoing CS for NMIBC, provide paired urine samples for cytology and CxBladder test. Patients with positive cystoscopy findings would undergo re-TURBT. 

Results: Thirty-five patients were enrolled from April to June 2019. Seven contaminated urine samples were excluded. The remaining cohort of 23(82%) males and 5(18%) females had a mean age of 66.69(36-89). Eight(29%) patients with positive cystoscopy finding underwent TURBT. All 8 patients also had positive CxBladder result. This shows that CxBladder has a sensitivity and negative predictive value (NPV) of 100%, specificity of 75% and positive predictive value (PPV) of 62% in predicting a positive cystoscopy finding. TURBT Histo-pathological findings showed 1(4%) low-grade Ta NMIBC, and 7(25%) inflammatory changes. Urine cytology was only positive in 1 patient with a positive cystoscopy finding. This led to a sensitivity of merely 13% and NPV of 74%, while specificity and PPV was 100% in predicting a positive cystoscopy finding.

Conclusion: CxBladder had high NPV and sensitivity which accurately predicted suspicious cystoscopy findings leading to further investigation. It has great potential to become a good adjunct to cystoscopy for surveillance of NMIBC.