Sensitivity and Specificity in Urine Bladder Cancer Markers - Is it that Simple?

Results of the Prospective Randomized UroFollow Trial Comparing Marker-guided Versus Cystoscopy-based Surveillance in Patients with Low/Intermediate-risk Bladder Cancer

BACKGROUND AND OBJECTIVE

A growing body of evidence suggests that the intensity of current follow-up in non-muscle-invasive bladder cancer (NMIBC) patients greatly exceeds clinical necessities. The UroFollow trial investigated the diagnostic accuracy of marker-based follow-up in patients with low/intermediate-risk NMIBC against the standard of care (SOC) for noninferiority (margin: <20%).

METHODS

Patients with Ta low- and high-grade (G1-2) NMIBC were randomized to the SOC or 6-monthly marker-based follow-up (algorithm comprising urine markers and ultrasound; marker-based surveillance regimen [MA]). After a negative 3-mo cystoscopy (white light cystoscopy [WLC]), only patients with a positive algorithm underwent WLC in the MA. End-of-study WLC was recommended at 3 yr to recurrence-free patients. Simultaneously, several innovative urine markers were examined.

KEY FINDINGS AND LIMITATIONS

In total, 214 patients were randomized to the SOC (n = 109) and MA (n = 105). The median follow-up was 2.4 yr; 30 and 29 cases of tumor recurrence were diagnosed in the SOC and MA arms, respectively. Sensitivity was 96.5% versus 81.5% (p = 0.1), with one and five Ta low-grade tumors being overlooked in the SOC and MA patients, respectively. No tumor progressing in stage or grade was missed. A total of 589 WLC procedures were performed in the SOC and 148 in the MA arm (p < 0.001). Among five other markers (ADX-Bladder, CellDetect, Bladder EpiCheck, UBC rapid, and Xpert bladder cancer monitor [BC-M]), Bladder EpiCheck and the Xpert BC-M showed similar performance to the algorithm.

CONCLUSIONS AND CLINICAL IMPLICATIONS

UroFollow is the first urine marker-based randomized trial in low/intermediate-risk NMIBC patients. We conclude that 6-monthly marker-based follow-up after negative 3-mo WLC is safe in this cohort. Results of contemporary urine markers suggest that their potential for use in marker-based surveillance, however, requires prospective confirmation.

Simulation of the effects of molecular urine markers in follow-up of patients with high-risk non-muscle invasive bladder cancer

A plethora of urine markers for the management of patients with bladder cancer has been developed and studied in the past. However, the clinical impact of urine testing on patient management remains obscure. The goal of this manuscript is to identify scenarios for the potential use of molecular urine markers in the follow-up of patients with high-risk non-muscle-invasive BC (NMIBC) and estimate potential risks and benefits. Information on the course of disease of patients with high-risk NMIBC and performance data of a point-of-care test (UBC rapid™), an MCM-5 directed ELISA (ADXBLADDER™), and 2 additional novel assays targeting alterations of mRNA expression and DNA methylation (Xpert bladder cancer monitor™, Epicheck™) were retrieved from high-quality trials and/or meta-analyses. In addition, the sensitivity of white light cystoscopy (WLC) and the impact of a urine marker result on the performance of WLC were estimated based on fluorescence cystoscopy data and information from the CeFub trial. This information was applied to different scenarios in patient follow-up and sensitivity, estimated number of cystoscopies, and the numbers needed to diagnose were calculated. The sensitivity of guideline-based regular follow-up (SOC) at 1 year was calculated at 96%. For different marker-supported strategies sensitivities ranging from 77% to 97.9% were estimated. Calculations suggest that several strategies are effective for the SOC. While for the SOC 24.6 WLCs were required to diagnose 1 tumor recurrence (NND), this NND dropped below 5 in some marker-supported strategies. Based on the results of this simulation, a marker-supported follow-up of patients with HR NMIBC is safe and offers the option to significantly reduce the number of WLCs. Further research focusing on prospective randomized trials is needed to finally find a way to implement urine markers into clinical decision-making.