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Comparing CxBladder Monitor to urine cytology as an adjunct to flexible cystoscopy for enhanced surveillance in non-muscle invasive bladder cancer (NMIBC)

R. Ramasamy¹, N. Amat¹, C. Ling¹, C. Chai¹, A. Fadzli¹, S. Kuppusamy¹, T. Ong¹

¹University Malaya Medical Centre, Surgery, Kuala Lumpur, Malaysia

Introduction:

Bladder cancer is the 10th most common cancer worldwide. They pose a high risk of recurrence and progression, hence an effective diagnostic, therapeutic and surveillance protocol is warranted. This study evaluates the diagnostic performance of the mRNA-based biomarker test, CxBladder Monitor in comparison to urine cytology in detecting recurrent bladder cancer.

Material and methods:

A total of 100 samples were collected and analysed over a 16-month period (August 2023 – December 2024). 12 samples were excluded due to shipment issue. Results were compared to urine cytology. All patients were subjected to flexible cystoscopy as well. Data was analysed using T-test to determine statistical significance.

Results:

CxBladder demonstrated a sensitivity of 100% and an NPV of 100%, indicating its strong ability to rule out cancer recurrence. However, its specificity was 35.2%, and PPV was 14.8%, suggesting a high false-positive rate. Comparatively, urine cytology exhibited a sensitivity of 63.6%, specificity of 71.4%, PPV of 24.1%, and NPV of 93.2%. Additionally, CxBladder monitor scores below 3.5 reported an NPV of 97% and sensitivity of 93%, reinforcing its reliability in identifying low-risk patients. The study also explored the relationship between CxBladder levels and tumor histology, stage, and grade. Its use was best described amongst those with carcinoma in-situ (p = 0.007), stage Ta (p= 0.01) and of low grade (p= 0.004).