Fluorescence in situ hybridisation in the diagnosis of upper urinary tract tumours.

BACKGROUND: Upper urinary tract (UUT) tumours are often a diagnostic challenge. Because of delayed diagnosis at an advanced stage, prognosis is less qualitative when compared to bladder tumours. There is, therefore, a need for reliable markers to improve diagnosis.

OBJECTIVE: Because of the difficulty in interpreting washing cytologies of the UUT, we evaluated the reliability of fluorescence in situ hybridisation (FISH) in the detection of upper tract urothelial cancer.

DESIGN, SETTING, AND PARTICIPANTS: A prospective, multicentre cohort study was carried out on 55 consecutive patients with a suspected UUT tumour.

MEASUREMENTS: Between May 2007 and May 2009, 55 consecutive patients (mean age 71.7 yr; range: 52-93) with a suspected urinary tract tumour were studied with intravenous pyelography, cytology, washing cytology, ureterorenoscopy, and endoscopic biopsies. The patients were followed for a mean observation time of 12.21 mo (range: 0.5-20; standard deviation: 6.12). A multicolour-FISH approach was performed on a liquid-based washing urinary cytology in all cases.

RESULTS AND LIMITATIONS: Twenty-one out of 55 patients had a histologically proven urothelial carcinoma, of which 10 had stage pTa disease, 6 had pT1 disease, 2 had pT2 disease, 2 had pTis disease, and 1 had pTx disease (6 G1, 6 G2, and 9 G3). Three patients had a papilloma, 2 had renal cell carcinoma, 27 had a negative histologic report, and 2 had a nondiagnostic histology. In total, 68 analyses were performed. The cytology was negative or doubtful in 60 out of a total 68 specimens (88.2%) and was suspicious or positive for malignancy in 7 (10.3%) specimens. One specimen was not diagnostic. FISH was negative in 37 of 68 analyses (54.4%) and positive in the other 30 analyses (44.1%). One FISH analysis was not diagnostic as a result of insufficient cellular material. The overall sensitivity of the cytology was 20.8% and of FISH 100%. The specificity was 97.4% for cytology and 89.5% for FISH. Even though this is the largest UUT cohort studied with FISH, the sample size is relatively small.

CONCLUSIONS: The UroVysion FISH test is a reliable method in the diagnosis of UUT tumours in cases with clinical suspicion but negative or doubtful cytology and no diagnostic histology.