Study of the safety and efficacy of maintenance treatment with intravesical BCG instillation in the prevention of superficial bladder tumours.

Maintenance treatment with complementary BCG instillations in the preventio n of superficial bladder tumour could improve the results of this immunothe rapy. This maintenance treatment is limited by accentuation of the adverse effects related to BCG. Objectives: To evaluate the impact of maintenance treatment on tumour recur rence and progression, and to evaluate the influence of adverse effects on maintenance treatment and the recurrence rate. Material and Methods: 72 patients were treated with six weekly instillation s of 81 mg of BCG (Immucyst(R))followed by three complementary instillation s 3, 6, 12, 18, 24, 30 and 36 months later Adverse effects (AE) were classi fied into four classes, according to their type, severity and duration, and were recorded prospectively for 518 instillations. An adverse effect score was determined for each patient. Results: 84.9% of patients did not present any recurrence, 12.5% developed recurrence and 2.6% progressed. The instillation regimen was completed by 1 9% of patients, the dose had to be decreased for 57% of patients and treatm ent had to be discontinued for 39% of patients. An initial adverse effect s core (AESi) greater than 1.5 was associated with an increased risk of disco ntinuation of treatment or reduction of the dosage during maintenance treat ment (p=0.01). Conclusions: Maintenance treatment was associated with a very,low recurrenc e and progression rate. We have established and validated an adverse effect severity scale and the consequences of these adverse effects on maintenanc e treatment. This scale could be used to prospectively define the most appr opriate maintenance instillation regimen, by preventively decreasing the do ses or deferring instillation.