FIG. 17:  For a physician there is a limited number of clinical scenarios where a marker can benefit the patient.  First, we cannot ignore cystoscopy, and so we know that if we look in a patient's bladder, we either see a cancer or we do not.  We might see no cancer or we might see some equivocal findings, such as an area that appears red or patchy. 

We know that when we compare marker performance with cytology performance, if we look in the bladder and see a tumor you already know what to do; we will take the patient to the operating room or biopsy the patient (Figure).  We also know that if a patient has a negative cystoscopy and a negative marker or cytology, we are not concerned and we will just monitor the patient. 

The problem is what to do if a marker is positive in the setting where we see no tumor or the findings are equivocal.  We know that cytology has a very high positive predictive value, and so if there are cancer cells in the urine, the current recommendation is to biopsy all these patients.^[5,6,10,11]  In other words, currently there is more certainty about what to do with a positive cytology than with a positive biomarker, unless inspection has clearly revealed the presence of a tumor.