Lotan - Figure 18
Identify Cancer Missed By Cystoscopy
FIG. 18: What about identifying cancer missed by cystoscopy? That is the main reason for using any adjuvant testing such as cytology or a urine-based tumor marker. The problem that we have currently is that no marker study has been designed to evaluate this particular goal. Most studies evaluate marker performance using cystoscopy, but only patients with abnormal cystoscopy go to the operating room to get a biopsy, and most patients with a positive marker do not get a biopsy.
The challenge with this is that it introduces a significant verification bias. How can we decide whether a marker is going to give us more information than cystoscopy if we do not biopsy patients with positive markers? To date, no study has been designed to evaluate a marker for the best possible use.
