A comparison of cytology and fluorescence in situ hybridization for the detection of urothelial carcinoma

Purpose: We determine the relative sensitivities of cytology and fluorescen ce in situ hybridization (FISH) for the detection of urothelial carcinoma. Materials and Methods: A mixture of fluorescent labeled probes to the centr omeres of chromosomes 3, 7 and 17, and band 9p21 (P16/CDKN2A gene) was used to assess urinary cells for chromosomal abnormalities indicative of malign ancy. A total of 280 urine specimens from 265 patients, including 150 with a history of urothelial carcinoma and 115 without a history of urothelial c arcinoma, were analyzed. FISH analysis was performed without prior knowledg e of clinical findings, that is biopsy, cystoscopy and cytology results. A positive result was defined as 5 or more urinary cells with gains of 2 or m ore chromosomes. Results: A total of 75 biopsies showed urothelial carcinoma at FISH analysi s among the 265 patients. The sensitivity of urine cytology for pTa (36 cas es), pTis (18) and pT1-pT4 (15) tumors was 47%, 78% and 60%, respectively, for an overall sensitivity of 58%. The sensitivity of FISH for pTa (37 case s), pTis (17) and pT1-pT4 (19) tumors was 65%, 100% and 95%, respectively, for an overall sensitivity of 81%. FISH was significantly more sensitive th an cytology for pTis (p = 0.046), pT1-pT4 (p = 0.025), grade 3 (p = 0.003) and all tumors (p = 0.001). The specificity of cytology and FISH among pati ents without cystoscopic evidence of urothelial carcinoma and no history of urothelial carcinoma was 98% and 96%, respectively (p = 0.564). Conclusions: The sensitivity of FISH for the detection of urothelial carcin oma is superior to that of cytology, and the specificity of FISH and cytolo gy for urothelial carcinoma are not significantly different. Further prospe ctive studies are required but FISH has the potential to improve significan tly the management of urothelial carcinoma.