[Quantification of bladder tumor antigen (BTA trak) and its correlation with bladder cancer grade and stage]

To analyze the efficacy of the BTA Trak test as a diagnostic marker for bladder cancer, determine its correlation with tumor grade and stage, compare its sensitivity with urinary cytology and its utility in urological conditions other than bladder cancer.

77 patients comprised the study; 33 with bladder cancer and 44 without. A urine sample was obtained from all patients for the BTA Trak test and another three samples for urinary cytology from each of the 33 patients with bladder cancer. Of the 44 patients without bladder cancer, 36 had conditions involving the urinary tract and 8 presented conditions without urothelial involvement. The BTA Trak test was repeated three months after treatment in 11 of the patients with bladder cancer and three months after the first test in 13 patients without bladder cancer.

Using BTA Trak threshold values of 14 U/ml as first reference and 50 U/ml as the value indicating clinical warning, these were found to be higher in 24 of 33 patients with bladder tumor (sensitivity 72.7%). By tumor stage, BTA Trak was positive in 12 of 21 pT1 (sensitivity 57%) and in 11 of 11 pT2 (sensitivity 100%). Concerning tumor grade, values were higher than threshold in 13 of 22 GI-II (sensitivity 59.9%) and 10 of 10 GIII (sensitivity 100%). Urinary cytology was positive in only 8 cases (sensitivity 24.4%). In the patients without bladder cancer, values are higher than threshold in 3 of 8 patients with urological conditions without urinary tract involvement and 14 of 36 with a probable urothelial involvement without tumor, accounting for an overall sensitivity of BTA Trak of 61.4%. The BTA Trak test three months after treatment showed lower value in 7 of 8 patients with bladder tumor and pretreatment values higher than threshold.

The BTA Trak test is a simple quantitative method with a high sensitivity for the diagnosis of bladder tumors, especially those in the advanced stages and grades. It is superior to cytology, although it has a lower specificity, particularly in conditions with urinary tract involvement.