Urinary UBC rapid and NMP22 test for bladder cancer surveillance in comparison to urinary cytology: Results from a prospective single-center study

Abstract

Background: Non-muscle invasive bladder cancer (NMIBC) is associated with high rates of recurrence, resulting in frequent follow-up cystoscopies. We evaluated the use of two point-of-care tests - the nuclear matrix protein 22 (NMP22) and urinary bladder cancer antigen (UBC) Rapid - compared to routine follow-up in patients with a previous history of NMIBC. Methods: 31 patients with cystoscopy-verified active bladder cancer, and 44 follow-up patients without disease as confirmed by cystoscopy were prospectively enrolled. All urine samples were analyzed by voided urine and bladder washing cytology, NMP22 and UBC rapid test (qualitatively and quantitatively). The best cutoff (highest Youden index; ≥6.7 ng/ml) for the quantitative UBC was determined by receiver operating characteristic curves. Results: Voided urine and barbotage cytology resulted in a sensitivity of 25.8% and 32.3%, and a specificity of 100% and 100%, while the NMP22 showed a sensitivity and specificity of 12.9% and 100%, respectively. The qualitative and quantitative UBC Rapid revealed a sensitivity of 61.3% and 64.5%, with a specificity of 77.3% and 81.8%. Barbotage cytology and qualitative UBC test proved to be the best dual combination with the highest overall sensitivity (77.4%). In contrast to barbotage cytology alone, sensitivity increased from 21.4% to 50% for detecting low-grade tumors, and from 43.8% to 100% for high-grade cancers, but reducing specificity from 100% to 77.3%. Conclusion: Compared to urinary cytology, UBC tests alone as well as UBC tests in combination with bladder washing cytology revealed higher sensitivities in detecting low- and high-grade tumors, but at the expense of a lower specificity. Thus, currently cystoscopy cannot be replaced by any of the evaluated methods.