Prospective Validation of Clinical Usefulness of a Novel mRNA-based Urine Test (Xpert® Bladder Cancer Monitor) for surveillance in Non Muscle Invasive Bladder Cancer.

OBJECTIVES

To assess the clinical performance characteristics of Xpert Monitor test for recurrence detection during surveillance of patients with non muscle invasive bladder cancer (NMIBC).

PATIENTS AND METHODS

Patient with previous history of NMIBC were included in the study. Voided urine specimens were collected for Xpert monitor analysis and cytology. Office cystoscopy was performed for all study participants with in patient biopsy specimen retrieval for positive or suspicious cases. Test characteristics were calculated based on cystoscopy/biopsy results and compared between Xpert and cytology.

RESULTS

Between March 2018 and May 2019, 181 patients including 168 (92.8%) males fulfilled the study criteria with median age 61 years, Primary tumors were low, intermediate, high risk in 2.8%, 22.7% and 74.5% of patients respectively. Biopsy proven recurrence was detected in 19 patients (10.4%). Xpert Monitor had a sensitivity of 73.7% with a negative predictive value (NPV) of 96.3%. Xpert Monitor was positive in all cases with high grade tumors (9 patients). Urine cytology showed sensitivity of 47% and an NPV of 93.2%. During follow up surveillance, out of 162 cystoscopy negative patients (CNP), 9.3% developed recurrence within 8 months. Xpert Monitor was found to be an independent predictor of early recurrence in CNP (HR=2.8, 95%CI=1.1-7.2, p=0.01).

CONCLUSIONS

Xpert Monitor urine test has a superior diagnostic performance for recurrence detection in NMIBC patients compared to urine cytology. It might be a helpful tool not only for excluding bladder cancer recurrence in those patients, but also for prediction of possible future early recurrence.