Fluorescence in situ hybridization performed on exfoliated urothelial cells in patients with transitional cell carcinoma of the bladder

Objectives. To evaluate comparatively fluorescence in situ hybridization (FISH) and cytology performed on exfoliated urothelial cells obtained from voided urine and bladder washings as a method of diagnosis and follow-up in patients with transitional cell carcinoma (TCC) of the bladder. Methods. Thirty patients with confirmed bladder TCC, 10 patients enrolled in cystoscopy follow-up for previous bladder tumors, and 10 patients with bladders free of tumor without a previous history of bladder TCC underwent cytologic examination and FISH performed on voided urine and bladder washing specimens. The FISH probes were targeted to chromosomes 7 and 9. Results. FISH had a sensitivity of 92% for high-grade tumors in both voided urine and bladder washing specimens, significantly greater than that of cytology at a sensitivity of 64% in voided urine and 67% in the bladder washing specimens (P = 0.02). The sensitivity of FISH and cytology were both low and not significantly different statistically from each other for the low-grade tumors. Monosomy of chromosome 9 correlated with early tumor recurrence. Polysomy of chromosomes 7 and 9 correlated with high-grade tumors (80% and 92%, respectively). Conclusions. According to our results, with the local cytopathology expertise, FISH performed on urothelial cells from voided urine has a sensitivity that supersedes that of cytology, making the former a valuable complementary method in the diagnosis and follow-up of patients with bladder TCC.