Influence of urinary tract instrumentation and inflammation on the performance of urine markers for the detection of bladder cancer.

OBJECTIVE

To evaluate the impact of inflammation and sampling on cytology, immunocytology, and fluorescence in situ hybridization (FISH) in comparison with NMP22 in hematuria patients. The specificity of urine markers for urothelial cancer is subject to exogenous factors. There is evidence that nuclear matrix protein 22 (NMP22) is influenced by urinary tract infection and instrumented urinary sampling (IUS).

METHODS

Samples from 1386 patients with histologic work-up were included. Cytology, immunocytology, FISH, and NMP22-enzyme-linked immunosorbent assay were performed. The presence of inflammation was evaluated by microscopy. The method of urine sampling was recorded in all cases. Any type of urinary tract manipulation was considered as IUS. False-positive results were compared with regard to the presence or absence of inflammation and mechanical manipulation.

RESULTS

In all, 1050 (75.7%) patients had no evidence of urothelial cancer. NMP22 results were false positive in 74.3% and 38.4% of patients with and without IUS (P < .0001). False-positive test rates of cytology, immunocytology, and FISH were not increased after manipulation. Inflammation led to a rise in false-positive NMP22 test results (85.3% vs 61.4%, P < .0001). The presence of inflammation did not change the rate of false-positive cytology, immunocytology, and FISH results.

CONCLUSION

This is the first study to investigate the impact of inflammation and IUS on cell-based urine markers. In contrast to the protein test NMP22, these factors did not impair the performance of cell-based tests. Hence, patients with positive cytology, immunocytology, and FISH results should undergo diagnostic work-up, even in the case of concomitant inflammation or IUS.