BACKGROUND: We examine the performance of cytology and FISH in the detection of urothelial carcinoma (UC), and explore the reasons for discrepant results, and potential clinical implications. METHODS: Urine samples from 89 patients were prospectively collected for simultaneous cytology and UroVysion FISH, and results correlated with concurrent biopsies and/or clinical or histologic follow-up data. Corresponding tissue biopsies, where available, were also evaluated by FISH. RESULTS: Sensitivity and specificity of cytology and FISH for the detection of UC was 54.8% and 92% and 50% and 88%, respectively. Only one of seven false-positive urinary FISH results proved to be an "anticipatory positive" on extended follow-up. Five of eight (62.5%) high grade (HG) carcinomas with false-negative urinary FISH, were negative due to the absence/paucity of FISH-detectable changes in the tumor cells. In atypical cytology cases, the FISH result did not assist in identifying UC. There was no significant difference between an atypical cytology result and a positive FISH result, with respect to the identification of patients with UC. CONCLUSIONS: We found urinary cytology to be more sensitivity and specific than FISH in the detection of UC, though the difference was not statistically significant. Up to 24% of HG UCs are FISH negative due to an absence of FISH-detectable abnormalities in the tumor cells. Paucity of neoplastic cells in the urine also contributes to false-negative FISH results in both HG and low grade tumors. Negative urinary FISH cannot be taken alone as indicating the absence of significant disease in patients with atypical cytology.
BACKGROUND: We examine the performance of cytology and FISH in the detection of urothelial carcinoma (UC), and explore the reasons for discrepant results, and potential clinical implications. METHODS: Urine samples from 89 patients were prospectively collected for simultaneous cytology and UroVysion FISH, and results correlated with concurrent biopsies and/or clinical or histologic follow-up data. Corresponding tissue biopsies, where available, were also evaluated by FISH. RESULTS: Sensitivity and specificity of cytology and FISH for the detection of UC was 54.8% and 92% and 50% and 88%, respectively. Only one of seven false-positive urinary FISH results proved to be an "anticipatory positive" on extended follow-up. Five of eight (62.5%) high grade (HG) carcinomas with false-negative urinary FISH, were negative due to the absence/paucity of FISH-detectable changes in the tumor cells. In atypical cytology cases, the FISH result did not assist in identifying UC. There was no significant difference between an atypical cytology result and a positive FISH result, with respect to the identification of patients with UC. CONCLUSIONS: We found urinary cytology to be more sensitivity and specific than FISH in the detection of UC, though the difference was not statistically significant. Up to 24% of HG UCs are FISH negative due to an absence of FISH-detectable abnormalities in the tumor cells. Paucity of neoplastic cells in the urine also contributes to false-negative FISH results in both HG and low grade tumors. Negative urinary FISH cannot be taken alone as indicating the absence of significant disease in patients with atypical cytology.