Two-year study on the application of the Paris system for urinary cytology in a cancer centre.

Abstract

The Paris system for reporting urinary cytology (TPS) was published in order to provide clear cytomorphological criteria for urine cytology specimens, focusing on high-grade urothelial lesions. The aim of this study was to evaluate the impact of implementing TPS and to correlate with available concomitant histological samples, accessing overall sensitivity and specificity. A retrospective analysis of urine cytology reports from 2017 to 2018 using TPS was carried out, with histological correlation to concomitant samples (up to 3months). Statistical analysis was performed with calculation of sensitivity and specificity, positive and negative predictive values and risk of malignancy (ROM) for all TPS categories. A total of 1660 specimens were evaluated. Histological specimens were available for 611 (36.8%) cases. Urine cytology categorised by TPS had 2.4% non-diagnostic cases, 87.1% negative for high-grade urothelial carcinoma (HGUC), 4.6% atypical urothelial cells, 2.7% suspicious for HGUC, 2.7% HGUC and 0.5% cases of other malignancies. Sensitivity, specificity, negative predictive value and positive predictive value were 40.0%, 99.3%, 88.2% and 92.3%, respectively. ROM of each category was 0% for non-diagnostic, 11.1% for negative for HGUC, 32.4% for atypical, 64.9% for suspicious for HGUC and 87.9% for HGUC and other malignancies. Our findings indicated that implementation of TPS provided a high specificity and predictive positive value for the detection of high-grade urothelial lesions, with proportionally increasing ROMs as categories progress from negative to positive.