FIG. 28:  Another novel use for urine-based biomarkers could be to predict response to bacillus Calmette-Guérin (BCG).  Currently there are no reliable methods available to predict which patients will respond to BCG.  In a study from MD Anderson Cancer Center in 126 patients who underwent BCG treatment with a median follow-up of 24 months, the patients who had a positive UroVysion® FISH assay during BCG treatment were 3−5 times more likely to have a recurrence and 5−13 times more likely to have disease progression.^[17]  However, patients with a negative FISH assay at baseline, 6 weeks, and 3 months demonstrated only an 8.3% recurrence rate compared with 48% for those who had a positive result at all three time points. 

This suggests that the FISH assay may identify patients with worse outcome for BCG.  This study needs validation and it is also unclear what conclusions can be drawn from it. Would you recommend early cystectomy based on FISH alone?  It's possible that the FISH assay, or a different marker might be used to identify patients who need alternative treatments.  It might also identify patients who would benefit from enrollment in clinical trials.