A very important study in treatment of non-muscle invasive bladder cancer has been released. Study compared one year to 3 years of BCG therapy in patients with low intermediate and high risk lateral cancer. The study also compared administration of BCG at lower dose versus full dose. Important findings of that the side effects of therapy are not significantly different from administering full dose or partial dose.
What is notable is that for high risk disease 3 years of therapy is more advantageous than a shorter course of 1 year of therapy. This study also demonstrated that for those treatment is more advantageous than a partial dose treatment.
While this study suggests that this may not matter as much for low and intermediate risk disease, the biology is apparently such that higher dose and longer duration of therapy is more beneficial as demonstrated for high-risk disease. My interpretation of this study is that it was not powered sufficiently to demonstrate the difference in outcomes for low risk disease.
At this point my interpretation of literature is that a full dose of BCG therapy should be administered to all patients who are thought to benefit from BCG treatment; maintenance BCG for 3 years and possibly with booster dosing for longer periods of time especially in patients with high risk disease is probably a safe and rational approach based on our knowledge of biology of the disease with high risk for recurrence years after diagnosis and the mechanism of action of maintenance BCG therapy.