DOES ISONIAZID REDUCE SIDE-EFFECTS OF INTRAVESICAL BACILLUS-CALMETTE-GUERIN THERAPY IN SUPERFICIAL BLADDER-CANCER - INTERIM RESULTS OF -ORGANIZATION-FOR-RESEARCH-AND-TREATMENT-OF-CANCER PROTOCOL-30911

Purpose: We analyzed the influence of the tuberculostatic agent isonia zid on the incidence and severity of adverse effects of intravesical b acillus Calmette-Guerin (BCG) therapy in patients with superficial bla dder cancer. Materials and Methods: In a prospective randomized multic enter study the side effects of intravesical instillations with Tice s train BCG with and without isoniazid were compared in patients with st ages pTa and pT1 bladder tumors. Isoniazid was given orally at a dose of 300 mg. daily at every instillation in an attempt to decrease the s ide effects of BCG. Results: No differences in local or systemic adver se reactions after intravesical immune therapy with BCG could be obser ved between patients treated with or without prophylactic isoniazid th erapy. However, analysis of liver function tests after BCG with isonia zid showed slightly more liver toxicity compared to BCG alone. Conclus ions: Prophylactic administration of isoniazid during BCG instillation s provides no decrease in any known side effect of BCG. In contrast, t ransient liver function disturbances are encountered slightly more fre quently when isoniazid is administered. The use of prophylactic isonia zid in patients treated with BCG is not recommended.