Fluorescence in situ hybridization for detecting urothelial carcinoma

Abstract

Because urothelial carcinoma (UC) is associated with a significantly high risk of disease recurrence and progression, patients with UC require long-term surveillance. Fluorescence in situ hybridization (FISH) has been shown to be more sensitive than cytology in the detection of UC. The current study evaluated the use of FISH for detecting UC. A pathology database was used to identify patients who had urine cytology and FISH performed at the study institution between 2004 and 2006. Urinary specimens were analyzed using UroVysion FISH probes for abnormalities in centromeric chromosomes 3, 7, and 17 and locus-specific 9p21. FISH results were correlated with cytologic findings and a minimal clinical follow-up of 24 months. A total of 1006 consecutive urinary specimens from 600 patients (448 men and 152 women) who were monitored for recurrent UC (915 specimens) or evaluated for urinary symptoms (91 specimens) were identified. On FISH analysis, 669 specimens were found to be negative for UC and 272 specimens were positive for UC. Sixty-five (6%) specimens were insufficient for FISH analysis. The sensitivity and specificity of FISH for UC were 58% and 66%, respectively, and 59% and 63%, respectively, when FISH and cytology results were combined. Factors contributing to decreased FISH sensitivity included the paucity or absence of tumor cells, low-grade tumors, degenerated cells, method of specimen collection, type of specimen, and obscuring inflammatory cells or lubricant. UroVysion FISH appeared to have good sensitivity and specificity for detecting UC in urinary specimens. It is important to correlate the FISH results with the cytologic findings.