FIG. 15:  It is important to remember is that all BCG maintenance is not created equal.  Panel D of this Figure^[13] shows the SWOG protocol that uses 6 weeks of induction BCG followed by 3 weeks of maintenance at 3 months, 6 months, and every 6 months thereafter for 3 years.^[14]  This is the only maintenance therapy that has shown a clear benefit over induction alone, both in papillary disease and in CIS. 

In Panel A shows the Kaplan-Meier curves for maintenance therapy where one instillation is used every 3 months^[15] and it is clear that maintenance adds little to induction alone.  In Panel B, we can see where the maintenance consists of one instillation every month, which again adds nothing to induction alone.^[16]  Panel C illustrates what I believe is the most common error that we urologists used to make, when we gave our patients 6 weeks of BCG, waited 6 months, and then provided another 6 weeks as maintenance therapy.  In this elegant study,^[17] it was shown that providing maintenance in this fashion did not enhance the efficacy over induction BCG alone.

In summary, what we need to remember is that not only is maintenance therapy important for BCG, but that not all maintenance therapies are created equal, and only the SWOG 6 + 3 protocol has been shown to have a clear benefit.^[13]