SUO 2022: “Remote” Monitoring in Urologic Cancer: The Case for Home Based Testing in Bladder Cancer

(UroToday.com) The 23rd Annual Meeting of the Society of Urologic Oncology held in San Diego, CA between November 30th and December 2nd, 2022 was host to a session on the real life impact of CxBladder tests for the diagnosis and surveillance of bladder cancer.

 

Dr. Sima Porten began her presentation by noting that there has been an “explosion” of “at home” tests, many of which have been approved by the US FDA. The most prominent example of this is the Cologuard stool DNA tests for colorectal cancer screening that has seen widespread adoption in the United States.

 

cxbladder_SUO_Sima Porten_0 

 

Dr. Porten focused her presentation on the utility of Cxbladder Monitor for the surveillance of bladder cancer patients. Cxbladder is a urine-based test that evaluates the gene expression of 5 mRNA biomarkers (MDK, HOXA13, CDC2, IGFBP5, CXCR2), which combined with patient clinical factors, allows for the calculation of a numerical value with a predefined cut-off value of 3.5. In a multicenter study of patients undergoing surveillance for recurrent urothelial carcinoma, Cxbladder Monitor was shown to have a:

  • Negative predictive value of 0.97
  • Sensitivity of 0.96 for detecting HG Ta, CIS, HG or LG T1 disease
  • Sensitivity of 0.86 for detecting LG Ta disease
  • A false negative rate of <1.5%
  • Not be affected by adjuvant BCG
  • Can be sent to a patients’ homes as a self-collected test

 

A pilot study was designed by Dr. Porten to evaluate the potential role of Cxbladder to minimize the frequency of cystoscopies in patients undergoing surveillance for bladder cancer, and thus reduce total patient burden (i.e. personal discomfort, financial time off work, travel, parking etc.). While this trial was hindered secondary to the COVID-19 pandemic, its framework and inclusion criteria were as follows:

Inclusion criteria:

NMIBC patients due for surveillance:

  1. ≥ 6 months from a primary diagnosis
  2. ≥ 9 months from a recurrent diagnosis
  3. ≥ 3 weeks from prior urinary instrumentation (voided urine only)
  4. ≥ 3 weeks from intravesical chemotherapy and ≥4 weeks from BCG
  5. No gross hematuria or active UTI

Study framework:

  1. Step 1: The clinic identifies, and orders Cxbladder Monitor for appropriate patients
  2. Step 2: Pacific Edge ships and instructs patients on performing the tests. The results are sent back to the clinic in 1 week
  3. Step 3: Telehealth/telephone follow up with the appropriate provider to review the results

 

Between March 2020 and June 2020, 92 patients from two institutions (UCSF and University of Michigan) were eligible for Cxbladder Monitor and were included in this study. As demonstrated in the table below, the majority of patients had intermediate to high-risk disease. Of note, patients in the Michigan cohort had a significantly longer mean duration between prior most recent recurrence and trial entry (63.9 versus 30.6 months),

 

cxbladder_SUO_Sima Porten_1 

 

As demonstrated in the figure below, of the 92 eligible patients, 66 (71.7%) had a Cxbladder Monitor score <3.5 and, thus, skipped immediate cystoscopy. After a median follow-up of 4 months (IQR: 3 – 6), no tumors were seen on follow-up in any of the patients.

 

Of the 24 patients with a Cxbladder Monitor score ≥3.5, all underwent an immediate cystoscopy with 9/24 (37.5%) patients having a visible tumor. All 9 patients underwent pathologic evaluation with the following findings:

  • cT0: 1 patient
  • cTa: 2 patients
  • cTis: 2 patients
  • cT2: 2 patients
  • UTUC: 1 patient
  • Unknown: 1 patient

Of note, in these 9 patients, all of whom had a “positive” Cxbladder Monitor score, six (66.6%) had a high-grade positive cytology findings, two (22.2%) had indeterminate findings, and one had a negative result (11.1%).

cxbladder_SUO_Sima Porten_2 

 

Summarizing these results, it appears that the performance of Cxbladder Monitor in this setting appears as such:

  1. Sensitivity: 100%
  2. Specificity: 78%
  3. Negative predictive value: 100%
  4. Positive predictive value: 33%

 

Based on the findings from this pilot trial, Dr. Porten proposed the following protocol for the management of patients with non-muscle invasive bladder cancer, with the goal of safely reducing the frequency of cystoscopic examinations:

cxbladder_SUO_Sima Porten_3 

 

But how do patients feel about foregoing more frequent cystoscopic examinations in favor of such protocols? Results of a patient satisfaction survey completed by 41/57 (72%) of UCSF patients demonstrated that:

  1. The test was easy to do at home: Median score of 5/5 (IQR: 4 – 5)
  2. Overall satisfaction was 5/5 (IQR: 4 – 5)
  3. When asked whether they would consider doing this test again in the future as a way to ‘skip’ one of their surveillance cystoscopies, the answers were as follows:
    1. Yes: 30/41 (73%)
    2. Maybe: 7/41 (17%)
    3. No: 3/41 (10%)

 

Dr. Porten concluded her presentation as follows:

  • COVID-19 has created changes to health care delivery pertaining to telehealth, remote work, and rationing resources (physical space)
  • We are experiencing a “new normal” in urologic care, which extends beyond the pandemic and that:
    • Reduces patient burden: without compromising short term oncologic outcomes
    • Reduces costs
    • Cxbladder Monitor safely reduces the frequency of surveillance cystoscopies in a real world setting and is acceptable to most patients as a home test

 

Presented by: Sima Porten, MD, MPH, Assistant Professor, Department of Urology, the University of California at San Francisco, San Francisco, CA 

Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 23rd Annual Meeting of the Society of Urologic Oncology (SUO), Nov 30 – Dec 2, 2022. San Diego, CA

References:

  1. Kavalieris L, et al. Performance Characteristics of a Multigene Urine Biomarker Test for Monitoring for Recurrent Urothelial Carcinoma in a Multicenter Study. J Urol 2017;197(6):1419-26.

 
Related Content: From Science to Clinical Utility: Cxbladder Monitor- Bladder Cancer Surveillance for Patients with Urothelial Carcinoma - Tamer Aboushwareb, Neal Shore & Josh Meeks

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