Comparison of conventional and liquid-based cytology using The Paris System for Reporting Urinary Cytology.

BACKGROUND: This retrospective study was conducted to compare the conventional cytospin method and ThinPrep liquid-based urinary cytology in diagnosing bladder cancer using The Paris System (TPS) of classification. METHODS: We retrieved files for 2020, at the Cytopathology Department of Laiko Hospital, of urinary cases diagnosed according to TPS. Cytospin and ThinPrep slides were separately reviewed and new diagnoses were rendered, then compared with the original diagnosis and histology when available. Risk of high-grade malignancy (ROHM) for each TPS category was assessed, along with accuracy parameters of each method and their combination. RESULTS: The study material comprised 100 cases of void urinary cytology classified as 20 high-grade urothelial carcinoma (HGUC = TPS5) cases, 20 of suspicion for HGUC (SHGUC = TPS4), 25 of atypical urothelial cells (AUC = TPS3), and 35 of negative for HGUC (NHGUC = TPS2). A single inadequate (TPS1) case and 4 of low-grade urothelial neoplasm (TPS6) were excluded as small in number. The ROHM was 95% for HGUC, 55% for SHGUC, 28% for AUC and 5.7% for NHGUC. Agreement with the original diagnosis was 86% for cytospin and 82% for ThinPrep. No significant differences were observed among the two techniques or their combination regarding sensitivity and specificity, with a mild advantage for cytospin. Interobserver reproducibility and repeatability were high. CONCLUSION: No significant differences were found concerning sensitivity and specificity between cytospin and ThinPrep when applying TPS criteria. TPS is a reliable classification scheme for either conventional/cytospin or liquid-based cytology, or their combination.

The Paris system classification for urinary cytology in patients under bacillus Calmette-Guerin treatment.

BACKGROUND: The role of urinary cytology as a diagnostic test for the detection and surveillance of urothelial cancer is crucial. Intravesical bacillus Calmette-Guerin (BCG) is the appropriate therapeutic strategy for patients with high-grade urothelial carcinoma (HGCU) or in situ carcinoma. We investigate how applicable is the Paris System for reporting urinary cytology (TPS) and how accurate is urinary cytology, in patients who undergo intravesical BCG instillations. METHODS: Our study contains urine samples from patients during the period January 1, 2017 to December 31, 2019. The inclusion criteria were patients with history of urothelial bladder carcinoma who had been treated with intravesical BCG instillation and cytology was followed by histology. We report our results and estimate the risk of high-grade malignancy (ROHM) for each TPS category and cytology accuracy. RESULTS: Four hundred thirty-eight samples corresponding to 146 patients fulfilled the criteria to be included in the study. There were 2 inadequate, 118 negative for high-grade urothelial carcinoma (NHGUC), 14 atypical urothelial cells (AUC), 6 suspicious for high-grade urothelial carcinoma (SHGUC), and 6 cases HGUC. Corresponding histology assessment has shown that the ROHM amounted to 0 for inadequate, 3.4% for NHGUC, 57% for AUC, 100% for SHGUC and HGUC. Sensitivity was 50%, specificity 100%, PPV 100%, NPV 91%, and accuracy 91.7%, considering inadequate, NHGUC and AUC as negative and SHGUC and HGUC as positive result. However, considering AUC a positive result, the accuracy parameters were different; sensitivity 83.3%, specificity 95%, PPV 76.9%, NPV 96.67%, and accuracy 93%. CONCLUSION: The Paris system for reporting urinary cytology can be safely applied to patients during follow-up after BCG intravesical administration.