CxBladder Monitor Testing to Reduce Cystoscopy Frequency in Patients with Bladder Cancer - Beyond the Abstract

Our study provides valuable insight into the utilization of CxBladder Monitor (CxM), an at-home mRNA-based urine test, as a viable adjunct to cystoscopy to de-intensify surveillance of non-muscle invasive bladder cancer (NMIBC).

Patients with NMIBC often experience recurrence and are subject to rigorous surveillance regimens, burdening patients and the healthcare system.1-4 To address this issue, we studied the effects of Cxbladder Monitor (CxM), an at-home mRNA-based urine test for recurrent NMIBC detection,8 on clinical outcomes and patient satisfaction during the COVID-19 pandemic at the University of California San Francisco and Michigan University. Eligible patients (>6 months from primary diagnosis, >9 month from recurrent diagnosis, >3 weeks from prior urethral instrumentation, >3 weeks from intravesical chemotherapy, and >= 6 weeks from Bacillus Calmette-Guerin) were contacted by the physician and nursing team after chart review to offer CxM home testing as an alternative to in-person cystoscopy. Scores ≥3.5 (CxM-positive) were considered positive (indicating the need for cystoscopy), while scores <3.5 (CxM-negative) were negative (low probability of recurrent UC), allowing patients to skip cystoscopy.

We enrolled 90 patients and over 80% were AUA high risk at diagnosis at a mean of 45 months (SD=41) from prior tumor (recurrent or primary) (Figure 1). Overall, we found that CxM had high sensitivity and negative predictive value (both 1.0), allowing 66 CxM-negative to safely skip surveillance cystoscopy without cancer recurrence upon next follow-up. 24 CxM-positive patients came in as scheduled for cystoscopy and 9 had findings necessitating biopsy, which demonstrated 1 T0, 2 Ta, 2 Tis, 2 T2, and 1 patient with UTUC; 1 patient’s biopsy was nondiagnostic of carcinoma (Figure 2). Patient satisfaction (median 5, IQR 4-5) and costs (78.8% no out-of-pocket expenses) were favorable.

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Figure 1. Months from prior tumor in patients eligible for CXM (N=81)

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Figure 2. CxMonitor study design and patient outcomes

This study's strengths and limitations both stem from its real-world implementation. Our study was the first to evaluate CxM in a home-test setting, as opposed to in-clinic testing which would undermine the practical benefits of the test. Our approach yielded favorable clinical outcomes and patient satisfaction, reducing burden of surveillance cystoscopies even in complex real-world settings. Nevertheless, our study’s practical implementation was associated with drawbacks. The follow-up period was limited to 12 months after initial testing (next scheduled cystoscopy) with 16/66 patients lost to follow-up. Furthermore, at Michigan, repeat CxM in place of follow-up cystoscopy was performed for select CxM-negative patients at patients’ request. These limitations highlight variations in care between institutions and the complexity of actual practice.

An important area for future research is the cost effectiveness of CxM in reducing the burden of cystoscopy on bladder cancer patients. CxM is currently reimbursed at $760 with 70% of claims from Medicare/Medicare advantage and 30% from commercial plans. A formal cost effectiveness analysis should be conducted to evaluate the potential savings associated with reducing the frequency of cystoscopy among NMIBC patients with negative CxM results. Additionally, future studies with larger sample sizes and follow-up would provide greater certainty in confirming our results.

At UCSF and Michigan, CxM continues to be offered to eligible patients to skip alternate cystoscopies (Figure 3). CxM may reflect a broader trend engendered by the COVID-19 pandemic of de-emphasizing solely in-person care and leveraging adjuncts such as at-home testing and telehealth as evolving methods of healthcare delivery.6-9

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Figure 3. Real world use of CxMonitor for bladder cancer surveillance

Written by: Kevin D. Li, Carissa E. Chu, Milan Patel, Maxwell V. Meng, Todd M. Morgan, Sima P. Porten

Department of Urology, University of California San Francisco, San Francisco, CA., Urology Service, Memorial Sloan Kettering Cancer Center, New York, NY., Department of Urology, University of Michigan, Ann Arbor, MI., Department of Urology, University of California San Francisco, San Francisco, CA.

References:

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  2. Sylvester RJ, van der Meijden APM, Oosterlinck W, et al. Predicting recurrence and progression in individual patients with stage Ta T1 bladder cancer using EORTC risk tables: a combined analysis of 2596 patients from seven EORTC trials. Eur Urol. 2006;49(3):466-465; discussion 475-477. doi:10.1016/j.eururo.2005.12.031
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