An evaluation of the real world use and clinical utility of the Cxbladder Monitor assay in the follow-up of patients previously treated for bladder cancer

Surveilling recurrent urothelial carcinoma (UC) requires frequent cystoscopy, which is invasive, expensive and time-consuming. An accurate urinary biomarker has the potential to reduce the number of cystoscopies required during post-treatment surveillance. To audit the clinical utility of a new surveillance protocol incorporating the Cxbladder Monitor (CxbM) test in real-world practice. Three hospitals implemented a new surveillance protocol. Patients were risk stratified, and then provided urine samples for CxbM testing. Low-risk CxbM-positive patients and all high-risk patients had cystoscopy at 2-3 months. Low-risk CxbM-negative patients had cystoscopy at ~ 12 months. 443 CxbM tests were conducted on samples from 309 patients: 257 (83.2%) low-risk and 52 (16.8%) high-risk. No pathology-confirmed recurrences were seen in low-risk CxbM-negative patients (n = 108) during the first post-CxbM cystoscopy undertaken a mean ± SD 10.3 ± 3.9 months after testing. Three recurrences were detected during cystoscopy at 2.7 ± 3.4 months in 53 low-risk CxbM-positive patients. In 49 high-risk patients, 39 (79.6%) were CxbM-negative with no pathology-confirmed recurrences. Ten high-risk patients (20.4%) were CxbM-positive with four confirmed recurrences; 2 high-grade and 2 low-grade. The median time to first cystoscopy was 12.13 (95% CI: 11.97-12.4) months in patients with a CxbM-negative result versus 1.63 (95% CI: 1.13-2.3) months in patients with a CxbM-positive result (p