Comparison of the Efficacy of Urine Cytology and Fluorescence in Situ Hybridization (FISH) for the Detection of Bladder Urothelial Carcinoma

Choi, Young Deuk; Cho, Nam Hoon; Chang, Soo Yeon; Rha, Sun Young; Chung, Hyun Cheo; Park, Kyeongmee

Abstract

PURPOSE: We compared the relative sensitivity and specificity between the urine cytology and fluorescence in situ hybridization (FISH) for the detection of urothelial carcinoma.
MATERIALS AND METHODS
FISH was used a mixture of fluorescent labeled probes to the centromeres of chromosomes 3, 7 and 17, and band 9p21 (P16/CDKN2A gene). Washing urine specimens were analyzed from 37 patients, including 27 with a known bladder urothelial carcinoma and 10 without a history of urothelial carcinoma. The sensitivity and specificity of the FISH was compared to that of urine cytology. FISH positivity was defined as more than 2 urothelial cells with an abnormal signal copy number of any one out of 4 probes.
RESULTS
In the bladder urothelial cancer group (n=27), the overall sensitivity of the urine cytology was 59.3% versus 88.9% for FISH (p=0.046). The sensitivity of urine cytology for pTa-1 (6 cases), and pT2-pT4 (11 cases) tumors were 37.5%, and 90.9%, respectively, and the sensitivity of FISH for pTa-1 (13 cases), and pT2-pT4 (11 cases) tumors were 81.3%, and 100%, respectively. The sensitivity of urine cytology were 33.3% (5 cases) for low grade tumors, and 91.7% (11 cases) for high grade tumors. The sensitivities of FISH were 80.0% (12 cases) for low grade tumors, and 100% (12 cases) for high grade tumors. FISH was significantly more sensitive than urine cytology for pTa-1 (p=0.021), low grade tumors (p=0.023) and all tumors (p=0.046). In the control group (n=10), the specificity of urine cytology and FISH was 90.0% and 100%, respectively (p=0.056).
CONCLUSIONS
With these results, the sensitivity of FISH for the detection of urothelial carcinoma is superior to that of urine cytology, and the specificity of FISH and urine cytology for urothelial carcinoma are not significantly different. FISH, in particular, is more sensitive in the detection of low grade, low stage bladder tumors. Further prospective studies are required but FISH can successfully be used as supplementary methods to detect low grade, low stage urothelial tumors.