BCG immunotherapy for transitional-cell carcinoma in situ of the bladder.

Prior to the advent of BCG immunotherapy, bladder carcinoma in situ often progressed to muscle invasion. Intravesical chemotherapy completely eradicates the disease in 50% of patients, but fewer than 20% remain disease free after 5 years. Complete responses have been reported in 70% or more of BCG treated patients, nearly two-thirds of which are durable. Controversy over the optimal induction and maintenance regimens for BCG immunotherapy remain, but SWOG investigators have demonstrated that complete response rates can be increased from the expected 73% to 87% with just three additional BCG instillations given at 3 months. In complete responders, maintenance BCG using three weekly treatments at 6-month intervals improves long-term complete response rates from 65% to nearly 90%. Caution must be exercised to avoid serious side effects.