Utility of UroVysion Fluorescence in situ Hybridization in Improving the Diagnostic Performance of Urine Cytology.

INTRODUCTION

The atypical urothelial cell (AUC) category in The Paris System (TPS) in urine cytology (UrCy) is a challenging area. This study aimed to evaluate the UroVysion fluorescence in situ hybridization (U-FISH) assay in predicting the outcome of AUC. Additionally, we explored the association of abnormal U-FISH results in high-grade urothelial carcinoma (HGUC) concerning muscularis propria invasion (MPI).

METHODS

This is a retrospective study, and U-FISH was done on archived Papanicolaou-stained smears. Four cohorts were included: non-neoplastic AUC (AUC-NN), neoplastic AUC (AUC-N), muscle-invasive HGUC (HGUC-MI), and muscle-free HGUC (HGUC-MF) outcome on histopathology (HPE) and with clinical follow-up of 12-29 months. U-FISH was evaluated for diagnostic purposes, and MPI and tumor stage prediction by urine FISH score (UFS; high vs. low) based on copy number gain of chromosomes (Chr).

RESULTS

U-FISH was performed on 70 cases (20 AUC-NN, 20 AUC-N, 15 HGUC-MI, and 15 HGUC-MF) and was successful in 58/70 (82.85%) cases. All UC cases showed polysomy of ≥2Chr, and all the AUC-NN cases reported non-neoplastic on HPE were negative for U-FISH. U-FISH picked up all carcinoma cases in the AUC-N cohort. Chr 3 polysomy was statistically significant in differentiating HGUC-MI from HGUC-MF and low-grade urothelial carcinoma cases. Chr 3 signals with a cut-off of 6 signals could identify MPI with a sensitivity of 80.95% and specificity of 41.94%. The UFS of the HGUC-MI group was significantly higher than HGUC-MF.

CONCLUSIONS

U-FISH successfully identified all cases of AUC with neoplastic outcomes. In the HGUC group, there was a difference in cases with and without MPI, which requires further confirmation in a larger prospective cohort.