Toward noninvasive follow-up of low-risk bladder cancer - Rationale and concept of the UroFollow trial.

Background: Follow-up recommendations for patients with nonmuscle invasive bladder cancer (NMIBC) are largely based upon expert opinion. A growing body of evidence suggests that current follow-up strategies for bladder cancer patients with low and intermediate risk represent overdiagnosis and may lead to overtreatment. The goal of this study is to explore the options of a noninvasive follow-up in patients with pTa G1-2/low-grade NMIBC.

Methods: The risks and options for a urine marker-guided, noninvasive follow-up of patients with pTa G1-2/low-grade NMIBC were defined and the study design for a prospective randomized trial (UroFollow) was developed based upon the current literature.

Results: The investigators postulated that follow-up of patients with pTa G1-2/low-grade NMIBC requires a high sensitivity of urinary tumor markers. However, data from prospective studies with prediagnostic urine samples are scarce, even for approved markers, and cross-sectional studies with symptomatic patients overestimate the sensitivity. So far, cell-based markers (e.g., uCyt+ and UroVysion) in urine appeared to have higher sensitivities and specificities in low-grade NMIBC than urine cytology and markers analyzing soluble tumor-associated antigens. Marker panels are more sensitive than single-marker approaches at the expense of a lower specificity. Given a prospective randomized comparison with a marker sensitivity of 80% compared to usual care with cystoscopy, the sample size calculation yielded that 62 to 185 patients under study per arm are needed depending on different recurrence rates.

Conclusions: Based upon these findings the UroFollow trial has been designed as a prospective randomized study comparing a noninvasive marker-based (UroVysion, NMP22, urine cytology, and ultrasound) follow-up with the current standard of care over a period of 3 years.