Assessment of Diagnostic Accuracy of Nuclear Matrix Protein 22 versus Urine Cytology for Detecting Bladder Cancer keeping Cystoscopy and Biopsy as Gold Standard: A Cross-sectional Study

Introduction: Bladder cancer is a common urological malignancy that requires early and accurate detection for effective treatment and improved patient outcomes. Traditional urine cytology is effective for high-grade tumours but has limited sensitivity for lowgrade cancers. Aim: To compare the sensitivity and specificity of the Nuclear Matrix Protein 22 (NMP22) test and urine cytology for bladder cancer detection, using cystoscopy and biopsy as the gold standard. Materials and Methods: This cross-sectional validation study was conducted at the Vydehi Institute of Medical Sciences and Research Centre in Bengaluru, Karnataka, India from August 2023 to August 2024, involving 42 patients with Transitional Cell Carcinoma (TCC). Urine samples were analysed using ALERE NMP22® and cytology, with cystoscopy and biopsy serving as the gold standard for diagnosing bladder cancer. Contingency tables were created to calculate sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), and diagnostic accuracy of NMP22 and urine cytology, using cystoscopy/biopsy as the gold standard. Results: The mean age of the study population was 56 years, with the mean age among males and females being 58.5 years and 51.3 years, respectively. NMP22 outperformed urine cytology in diagnosing bladder cancer, with a sensitivity of 76.32% (32/42) versus 31.58% (13/41), and both tests had 100% specificity and PPV. NMP22’s NPV was 30.77%, compared to 13.33% for cytology. Overall accuracy for NMP22 was 78.57% (33/42), while the accuracy for cytology was 38.10% (16/42). Conclusion: The NMP22 is more sensitive than urine cytology for detecting bladder cancer. While cytology remains valuable for its specificity and confirmatory role, NMP22 offers a superior diagnostic option, particularly for the early detection of aggressive tumours. Future research should explore combining NMP22 with other diagnostic methods to further enhance early detection and improve patient outcomes.