Utility of Cell Block with p53 Immunostain in Diagnosing Urothelial Carcinoma

Background: Urine cytology is an initial noninvasive screening test done in patients with suspected urothelial carcinoma. The objective of this study was to compare the sensitivity of conventional smear cytology with cell block technique for the diagnosis of malignant cells in urine and to assess the efficacy of p53 immuno-marker in the diagnosis and prognosis of urinary bladder cancer. Methodology:   The study was carried out in the department of Histopathology, Pakistan Institute of Medical Sciences(PIMS), Islamabad. Cell blocks and cytology smears and were prepared from urine samples of 80 patients of urothelial carcinoma and p53 stain was applied. Data was analyzed using version 21. Sensitivity of conventional smear and cell block techniques were calculated for both low and high grade urothelial carcinomas. Results:The sensitivity of detecting atypical cells using conventional smear was 31% and 70.6% for low grade and high grade urothelial tumors respectively. The sensitivity increased to 41.4% and 84.3% for low and high grade urothelial carcinomas respectively with cell block technique. Positive p53 stain was seen in 13.8% of cases with low grade tumors and 66.7% cases with high grade tumors. Chi-square test was used to find the association of cytology findings with the histologic grade. Conclusion: Sensitivity of urine cell blocks is higher than the conventional smear method for detecting high grade lesions. It can be used as an efficient non-invasive technique and an adjunct tool for the determination of disease relapse and overall survival in patients. Keywords: Carcinoma, Cytology, P53 Protein, Urine