HUMAN COMPLEMENT FACTOR H RELATED PROTEIN TEST FOR MONITORING BLADDER CANCER

Abstract

The BTA stat test is a rapid, noninvasive, qualitative urine test that detects bladder tumor associated antigen (human complement factor H related protein) in urine. We compared BTA stat test to voided urine cytology in patients monitored for bladder cancer in a prospective trial, and determined whether this test is effective in detection of recurrence not seen by regular cystoscopy. A total of 445 consecutive patients with bladder cancer were studied. A voided urine sample was obtained before cystoscopy and divided for culture, cytology and BTA stat testing. In cases of a positive BTA stat test but negative cystoscopy, excretory urography or renal ultrasound, random biopsies and collected ureteral urine samples for ureteral cytology were obtained. The overall sensitivity and specificity as well as positive and negative predictive values for BTA stat test, cytology and their combination were calculated. Of the 445 patients 118 (26.5%) had bladder cancer recurrence on cystoscopy, which was detected by BTA stat test and cytology in 63 (53.4%) and 21 (17.8%), respectively. Of the remaining 327 patients not having recurrent tumor on cystoscopy 81 (24.8%) had a positive BTA stat test. Excretory urography or renal ultrasound and random biopsies in 48 (59.3%) of these patients revealed 7 recurrences, making the total number of recurrent tumors 125 of 412 (30.3%). The overall sensitivities and specificities for the BTA stat test, cytology and their combination were 56.0%, 19.2%, 60.0% and 85.7%, 98.3% and 85.0%, respectively. The sensitivity for detection of recurrent tumor on BTA stat test is superior to that of voided urine cytology in all bladder cancer categories, whereas the specificity of voided urine cytology is higher than that for BTA stat test. However, a sixth of the patients with apparent false-positive BTA stat test results chosen for further investigation had recurrent tumors that were not found on routine cystoscopy. Although the sensitivity and specificity were highest when both tests were used, the differences were not significant overall. Therefore, the BTA stat test could potentially replace urine cytology for followup of superficial bladder cancer.