Evaluation of the BTA tests for the detection of bilharzial related bladder cancer: The Cairo experience

Objective: To evaluate the clinical performance of the BTA stat test and th e BTA TRAK assay in the diagnosis of bilharzia-related bladder cancer and t o calculate a new 'Egyptian' cut-off value for the BTA TRAK (quantitative) assay. Methods: Urine samples of 149 individuals were tested for the presence of t he human complement factor H-related protein, the antigen detected by the B TA stat and BTA TRAK tests. The group consisted of 53 healthy volunteers, 2 0 patients with active bilharziasis, 11 patients with other urologic disord ers including prostate cancer, and 65 patients with histologically proven b ladder cancer. All samples were obtained prior to surgery or therapy. Results: The BTA stat test was positive in 64 of 65 samples from patients w ith bladder cancer, for an overall sensitivity of 99%. With a BTA TRAK assa y cut-off of 60 U/ml (set at 97% specificity in the healthy population), th e sensitivity of the TRAK assay was 94%. There was no statistically signifi cant difference between the sensitivities of the two BTA tests in patients diagnosed with squamous cell carcinoma and those with transitional cell car cinoma. The overall specificity of the BTA stat test was 67% ranging from 1 5% in patients with bilharziasis to 94% in healthy volunteers. The overall specificity of the TRAK assay was 66%, again with negative results in 15% o f the patients with bilharziasis. Conclusions: The BTA stat test and TRAK tests are extremely sensitive in th e detection of bladder cancer in the Egyptian population. Positive results (85%) are also observed in patients with active bilharziasis, which often l eads to bladder cancer. Longitudinal follow-up of these positive cases is n eeded to determine whether these positive results are false or predictive o f bladder cancer. Copyright (C) 2001 S. Karger AG, Basel.