BCG can best be described as very effective at preventing and delaying recurrences. Its actual effect depends on the grade and stage of tumor being treated as well as the dose and timing of the treatments. Most urologists will give weekly instillations of BCG for 6 weeks. Cystoscopy is then performed 6 weeks after the last treatment to look for tumor recurrences.
Depending on the tumor pathology, your urologist may then elect to give you 3 more weeks of BCG at 3 months or a more aggressive regimen, repeating the BCG treatments every 6 months for 3 years. In patients who have a positive cytology after a full 6-week course of BCG, a second 6-week course of BCG may be necessary.