A Study on Association of Urine Cytology as Reported by the Paris System with Histopathology and p53 Expression in Urinary Bladder Epithelial Neoplasms EC04-EC09
Dr. Anadi Roy Chowdhury,
Swades Apartment, Flat B4, 61 James Long Sarani, P.O. Thakur Pukur, Kolkata-700063, West Bengal, India.
Introduction: Urinary bladder cancer is the ninth most common cancer worldwide. Urine cytology is a simple yet effective tool for detecting high grade urothelial carcinomas. The grade of the tumour can be detected on histopathology and confirmed by immunohistochemistry as p53 mutations have well established association with invasive urothelial cancers and high grade lesions.
Aim: To evaluate urine cytology as an investigational tool for urothelial carcinomas using The Paris System. The main goal was to evaluate the diagnostic accuracy of this system. The histopathological features and immunohistochemical expression of p53 were evaluated to confirm the diagnosis.
Materials and Methods: This study was a descriptive cross- sectional study, conducted in the Department of Pathology in collaboration with the Department of Urosurgery, R.G. Kar Medical College and Hospital, Kolkata, over a time period of 18 months (January 2017-June 2018). The study population comprised patients presenting with haematuria and urinary bladder neoplasm. Preoperative cytological examination of urine was reported as per the Paris System. Results were correlated with Histopathology. Immunochemical estimation of p53 expression was done. Test thresholds were selected for cytology, histopathology and immunohistochemistry. Chi-square tests were performed for correlation between the three tests.
Results: Using Suspicious for High Grade Urothelial Carcinoma (SHGUC) as diagnostic threshold, the sensitivity and specificity of urine cytology in detecting high grade lesions was evaluated to be 89.80% and 69.23% respectively. Immunostaining with p53, keeping 10% positivity in the nuclei as threshold, gave a sensitivity of 89.8% and specificity of 53.85%. Both immunohistochemistry and cytology as reported by The Paris System, were found to be significant in detecting high grade cancers (p<0.05). The tests were also done using other cut-offs and validation of the best threshold was estimated.
Conclusion: Significant association was found between p53 positive cases and cases diagnosed as SHGUC and High Grade Urothelial Carcinoma (HGUC) in cytology as reported by TPS with cases that showed presence of high grade cells on biopsy.