Assessment of Urothelial Carcinoma Using Probe-Based CLE During Flexible Cystoscopy

Overview

This prospective pilot study evaluated the diagnostic accuracy and yield of probe-based confocal laser endomicroscopy (CLE) using the CystoflexF probe during flexible cystoscopy for suspicious papillary bladder lesions. The study demonstrated that CLE imaging with the smaller CystoflexF probe is feasible and provides real-time cellular-level assessment, with diagnostic accuracy compared to the ultra-high-definition CystoflexUHD-R probe during rigid cystoscopy.

Background

Bladder cancer is the 10th most common cancer worldwide, with urothelial carcinoma accounting for over 90% of cases in high-income countries. Non-muscle invasive bladder cancer (NMIBC) comprises approximately 75% of new diagnoses but has high recurrence rates, necessitating frequent cystoscopic surveillance and repeat resections. Conventional outpatient cystoscopy lacks in-vivo histopathologic characterization, leading to many unnecessary transurethral resections. Confocal laser endomicroscopy (CLE) offers real-time optical biopsy capabilities, potentially improving diagnostic accuracy during cystoscopy. While the ultra-high-definition CystoflexUHD-R probe has shown promise during rigid cystoscopy, its size limits use with flexible cystoscopes, prompting evaluation of the smaller CystoflexF probe.

Data Highlights

Key Findings

• Probe-based CLE with the CystoflexF probe during flexible cystoscopy is feasible for real-time imaging of suspicious papillary bladder lesions.
• The diagnostic accuracy of the CystoflexF probe for identifying and grading urothelial carcinoma was assessed against histopathology as the reference standard.
• Interobserver variability was evaluated, showing reproducibility of CLE image interpretation between experienced observers.
• The CystoflexF probe, despite having lower imaging resolution than the CystoflexUHD-R probe, demonstrated promising diagnostic performance.
• Direct paired comparison with the CystoflexUHD-R probe during rigid cystoscopy was performed to contextualize diagnostic yield and accuracy.
• Non-diagnostic CLE images were reported but excluded from accuracy calculations to maintain data integrity.

Clinical Implications

The use of the smaller CystoflexF CLE probe during flexible cystoscopy enables in-vivo, real-time histopathologic assessment of bladder lesions in an outpatient setting, potentially reducing unnecessary repeat resections. This technique may improve diagnostic confidence and patient management by complementing standard cystoscopy without requiring rigid instruments. Further validation could support integration into routine NMIBC surveillance protocols.

Conclusion

Probe-based CLE with the CystoflexF probe during flexible cystoscopy is a feasible and promising diagnostic tool for urothelial carcinoma assessment, offering real-time cellular imaging with acceptable diagnostic accuracy. This approach may enhance bladder cancer surveillance by providing immediate histologic insights during outpatient procedures.

References

1. Liem et al. -- Diagnostic features of CLE for urothelial carcinoma
2. CLETUR Trial Protocol (NCT05273593)
3. STARD Guidelines -- Reporting diagnostic accuracy studies
4. IDEAL-D Recommendations -- Exploratory study design