Performance of fluorescence in situ hybridization in detecting lower versus upper tract urothelial carcinoma

Many studies have evaluated the performance of fluorescence in situ hybridization (FISH) in detecting urothelial carcinoma, while few of them compared it in detecting bladder cancer (BC) vs. upper tract urothelial carcinoma (UTUC). This study aimed to determine and compare the FISH performance in detecting BC and UTUC.

Data of patients with suspected urothelial carcinoma (UC) who accepted FISH from January 2021 to April 2023 were retrieved. The sensitivity and specificity of FISH in detecting BC and UTUC were determined and compared.

A total of 145 BC, 62 UTUC, and 170 non-UC patients were included. No significant differences existed between BC and UTUC cohorts in FISH sensitivity (46.2% vs. 51.6%, p = 0.476) and specificity (100% vs. 95.8%, p = 0.271). FISH sensitivity was significantly higher in high-grade vs. low-grade BC and increased gradually from Ta to ≥T2 group. It was also higher in patients with multiple or large tumors or older age. Similar tendencies were observed in UTUC. FISH sensitivity was higher in BC vs. UTUC in detecting T1 or ≥T2 tumors (p < 0.05). Multivariate analysis confirmed the tumor stage and the patient's age as predictors of FISH results in BC.

FISH demonstrated overall similar sensitivity and specificity in detecting BC vs. UTUC, while the sensitivity was higher in BC for T1 or ≥T2 tumors. FISH was more sensitive in detecting more invasive or advanced tumors. The tumor stage and the patient's age were predictors of the FISH result in BC.