Real-world data demonstrate efficacy of genomic urine test for bladder cancer recurrence

The Cxbladder Monitor (CxbM) genomic urine test showed clinical utility when incorporated into a surveillance protocol for bladder cancer recurrence, according to real-word findings published in BMC Urology.¹

The CxbM technology accurately identified a high percentage (77.8%) of patients for whom only 1 annual cystoscopy was sufficient to safely surveil their risk of bladder cancer recurrence. Additionally, “Including CxbM in the protocol for patient surveillance [reduced] the average number of annual cystoscopies by approximately 39%, thereby sparing patients the potential discomfort and anxiety, without compromising detection rates,” the investigators, wrote.

Post-treatment surveillance of patients with urothelial carcinoma involves frequent visits to the clinic to receive cystoscopy. Beyond being time-consuming, the procedure is invasive and costly. The investigators sought to determine whether incorporating CxbM into the management of patients at risk of recurrence could lower the number of cystoscopies that a patient required.

A protocol for surveilling recurrent disesase in patients previously treated for urothelial carcinoma was implemented at 3 public health providers in New Zealand. Patients were stratified by recurrence risk and then they provided urine samples which were tested with the CxbM assay. All patients at high risk of recurrence, as well as those at low-risk of recurrence who tested CxbM-positive, received cystoscopy every 2 to 3 months. Low-risk patients with negative CxbM results received cystoscopy approximately every 12 months.

Overall, the analysis included samples from 309 patients, 83.2% (n = 257) of whom were low-risk and 16.8% (n = 52)of whom were high-risk. At the time of the data analysis 253 low-risk patients and 49 high-risk patients were evaluable. Of these patient groups, 161 and 47, respectively, had received at least 1 cystoscopy. The mean time since primary cancer was 6.5 years in the low-risk group and 4.5 years in the high-risk group.

Among the 108 low-risk patients who tested CxbM-negative, there were no pathology-confirmed recurrences detected at the first cystoscopy following CxbM. These cystoscopies occurred at an average of 10.3 months (SD, ± 3.9) following testing. In the 53 low-risk patients who were CxbM-positive, cystoscopy conducted at a mean of 2.7 months (SD, ± 3.4) after testing detected 3 recurrences.

In the high-risk group, 79.6% (n = 39) of 49 patients tested CxbM-negative with no pathology-confirmed recurrences. The other 20.4% (n = 10) of the high-risk group tested CxbM-positive. In these patients, there were 4 confirmed recurrences, 2 of which were high-grade and 2 of which were low-grade.

The median time to initial cystoscopy was 12.13 months and 1.63 months among patients with CxbM-negative and CxbM-positive results, respectively. No patients died of cancer throughout the 35 months of follow-up, and there were no positive cases of recurrence that were missed.

“This audit demonstrated the real-world clinical utility of CxbM as a rule-out test for both low- and high-risk patients undergoing surveillance for recurrent urothelial carcinoma. The data showed no advantage to patients being segregated on the basis of risk prior to the use of CxbM,” the investigators wrote.

“Our study also showed that CxbM effectively identified patients at higher risk of recurrence regardless of the time since the original urothelial carcinoma diagnosis, and therefore can be implemented at any time during the post-treatment course of the disease. All three centers included in this audit now use the CxbM test in their clinical protocols to rule-out low risk patients and prioritize urothelial carcinoma patients for follow-up cystoscopy.”

Reference

1. Koya M, Osborne S, Chemaslé C, et al. 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 [published online February 12, 2020]. BMC Urol. doi: 10.1186/s12894-020-0583-0