Multicenter trial of the quantitative BTA TRAK assay in the detection of bladder cancer

Background: Human complement factor H-related protein (hCFHrp) is produced by several bladder cancer cell lines and may be useful as a cancer marker. The aim of this study was to compare urinary hCFHrp and cytology for the de tection of bladder cancer found by cystoscopy in patients with suggestive s igns, symptoms, or preliminary test results. Methods: The BTA TRAK(TM) assay, a quantitative enzyme immunoassay for the: bladder tumor-associated antigen in urine, was compared with exfoliative c ytology in 220 patients (155 men, 65 women; mean age, 64.2 years) presentin g with signs, symptoms, or preliminary diagnostic results suggestive of thi s disease. Cystoscopy was the standard of detection. Results: In the 100 patients found to have bladder cancer, the overall sens itivities of the BTA TRAK assay (at a,previously determined decision thresh old of 14 kilounits/L) and cytology:were 66% (66 of 100) and 33% (33 of 100 ), respectively (P <0.001). The BTA TRAK assay proved to be: statistically more sensitive than cytology for tumor grades I and II and for stage T-a, a nd TI tumors. In contrast, the overall specificity of the BTA TRAK assay in the 120 patients without cystoscopically confirmed bladder cancer was 69% (83 of 120) and that of cytology was 99% (119 of 120; P < 0.001). The speci ficity of the BTA TRAK assay was higher in patients without benign or malig nant genitourinary disease other than bladder cancer (76%; n = 89) than in patients with these conditions. When the BTA TRAK assay and cytology were u sed together such that a positive result in either test: was scored as,posi tive and the results compared with:those of the: BTA TRAK assay alone, incr eases in overall, sensitivity and equivalent specificity were observed. Conclusion: Because of its relatively high sensitivity, the BTA TRAK assay could complement cytology as an adjunct to cystoscopy in the diagnosis and follow-up of most patients with bladder cancer. (C) 1999 American Associati on for Clinical Chemistry.