Comparative evaluation of the diagnostic performance of the BTA stat test, NMP22 and urinary bladder cancer antigen for primary and recurrent bladder tumors.

PURPOSE

We compared overall sensitivity and specificity of the urinary bladder cancer antigen enzyme-linked immunosorbent assay (UBC, IDL Biotech, Sollentuna, Sweden), BTA stat test (Bion Diagnostic Sciences, Inc., Redmond, Washington) and NMP22 test kit (Matritech, Newton, Massachusetts), and the differential sensitivity regarding the histological pattern of tumors.

MATERIALS AND METHODS

A total of 213 patients with clinical and/or imaging signs of bladder cancer provided a single voided urine sample for the bladder cancer antigen, BTA stat test and NMP22 before cystoscopy. Of these patients 95 were monitored for superficial bladder cancer, while the remaining 118 had no history of bladder cancer. All detected bladder tumors or suspicious lesions were resected transurethrally. A group of 21 age and sex matched healthy volunteers were also evaluated with the same tests.

RESULTS

Bladder cancer was confirmed histologically in 118 patients, of whom primary and recurrent tumors were in 68 and 50, respectively. The optimal cutoffs calculated with receiver operating characteristics curves were 8 units per ml. for NMP22 and 12 microg./l. for bladder cancer antigen. Overall sensitivity and specificity were 72.9% and 64.6% for the BTA stat test, 63.5% and 75.0% for NMP22, and 80.5% and 80.2%, respectively, for bladder cancer antigen. Bladder cancer antigen proved significantly more sensitive than NMP22 for detecting bladder cancer (p = 0.001) but not more than the BTA stat test, while the specificity of it was significantly higher than that of the BTA stat test (p = 0.009). Bladder cancer antigen had a sensitivity of 80.7% for stage Ta tumors, which was significantly higher than NMP22 (52.6%, p = 0.001) and the BTA stat test (57.9%, p = 0.01). In grade I tumors the sensitivity of bladder cancer antigen (70%) did not differ significantly than that of the BTA stat test (50%) and NMP22 (50%, p = 0.14). Bladder cancer antigen had the least false-positive results in patients with a history of bladder cancer and negative cystoscopy, and those with urological disease other than bladder cancer.

CONCLUSIONS

Our data indicate that bladder cancer antigen may be a more potent diagnostic marker for bladder cancer than NMP22 and the BTA stat test based on the higher sensitivity for detecting low stage and low grade tumors, and the higher specificity. The contribution of these tests for detection of bladder cancer should still be considered adjunctive to cystoscopy.