The Bard BTA test as a prognostic indicator in mitomycin-treated superficial bladder cancer

Introduction: The Bard bladder tumour antigen (BTA) dipstick test is a latex-agglutination antibody test which detects elements of the cytoskeleton not normally present in the urine, but which appear in any condition which disrupts the urothelial basement membrane. Mitomycin treatment of superficial bladder cancer is thought to act by producing a direct irritant effect on the urothelium. It was therefore postulated that a positive BTA test after a course of intravesical mitomycin therapy would indicate that an inflammatory reaction had been induced in the urothelium sufficient to decrease the likelihood of tumour recurrence. Patients and methods: Forty-seven patients with newly diagnosed superficial bladder cancer were recruited. All cases were diagnosed by endoscopie biopsy; 12 patients were excluded because of a positive BTA test before chemotherapy. Each patient underwent a 6-week course of intravesical instillation of mitomycin; BTA dipstick testing was performed before each instillation and before a check cystoscopy performed 3 months after the initial diagnosis. Results: Of 35 patients initially negative for BTA, 17 were positive by the time of the check cystoscopy. These patients had no recurrence of tumour at that time. Of the remaining 18 patients, 14 were persistently negative. These were all found to have recurrent tumour at check cystoscopy. The other four patients had some positive results during treatment, but were negative at check cystoscopy. These also had tumour recurrence. Conclusions: The Bard BTA test may be a useful investigation in the follow-up of patients with superficial bladder cancer treated with mitomycin. The results also supports the theory that the greater the degree of inflammation produced, the less likely there is to be tumour recurrence.