Quantitative cytomorphological comparison of SurePath and ThinPrep liquid-based cytology using high-grade urothelial carcinoma cells

Objective In The Paris System for Reporting Urinary Cytology (TPS), the important cytomorphologic features for diagnosing high-grade urothelial carcinoma (HGUC) are a nuclear-to-cytoplasmic (N:C) ratio exceeding 0.7, hyperchromasia, coarse chromatin, and irregular nuclear borders. However, the quantitative cytomorphologic assessment of HGUC cells using SurePath slides is rare. Therefore, we evaluated HGUC cells on SurePath slides quantitatively using a digital image analysis system and compared these data with ThinPrep data. Methods The same urine samples were divided into two aliquots and used to prepare SurePath and ThinPrep slides. We used ImageJ to measure the N:C ratio, hyperchromasia, and irregular nuclear borders for HGUC cells on SurePath and ThinPrep slides. Results The total number of analyzed HGUC cells on SurePath slides was 981, versus 889 on ThinPrep slides. Hyperchromasia and irregular nuclear borders were significantly more severe on SurePath slides than on ThinPrep slides. Conversely, the N:C ratio did not differ between the methods. Additionally, HGUC cells with N:C ratios exceeding 0.7 were present on almost all slides for both methods. Conclusions Our data indicated the reasonableness of using the N:C ratio as the major criterion for the TPS on both SurePath and ThinPrep slides, and an N:C ratio cutoff of 0.7 was suitable for identifying HGUC cells. Meanwhile, the severity of hyperchromasia and irregular nuclear borders differs between the processing methods.