Increased risk of malignancy for non-atypical urothelial cell groups compared to negative cytology in voided urine. Morphological changes with LBC

Comparison of urine cytology diagnostic reports before and after the implementation of the Paris System classification system in China

OBJECTIVE

In 2013, The Paris System for Reporting Urinary Cytology (TPS) was developed as a uniform practical urine cytology system that could be applied worldwide. Here, we investigated the effectiveness of TPS diagnostic approach compared with that of the traditional urine cytological diagnosis method used in China.

METHODS

Based on the diagnostic criteria of TPS, 412 urine samples from 143 patients with histological follow-up data were retrospectively analysed, and the diagnoses were compared with the original cytological diagnoses.

RESULTS

In total, 110 patients were histologically diagnosed with high-grade urothelial carcinoma (HGUC), and 33 patients were diagnosed with low-grade urothelial neoplasia. Based on the traditional urine cytological analysis method, 50 patients (34.9%) were diagnosed as negative, 48 patients (33.6%) were diagnosed as having atypical urothelial cells, and 45 patients (31.5%) were diagnosed as positive. After reclassification using TPS, urine samples from 11 cases (7.7%) were categorised as unsatisfactory, 34 cases (23.8%) were negative, 21 cases (14.7%) were categorised as having atypical urothelial cells, 12 cases (8.4%) were diagnosed as suspicious for HGUC, 59 cases (41.2%) were diagnosed with HGUC, and six cases (4.2%) were reclassified as having low-grade urothelial neoplasia. Thus, after implementing TPS criteria, the sensitivity for positive malignancy diagnoses (HGUC alone) increased from 38.2% to 50.9%, while the specificity of the diagnosis was barely changed.

CONCLUSIONS

The Paris System for Reporting Urinary Cytology greatly contributes to the standardisation of urine cytology reports and significantly improves the diagnostic sensitivity for HGUC.