Oral or intravesical bacillus Calmette-Guerin immunoprophylaxis in bladder carcinoma. A total of 71 patients with superficial transitional cell carcinoma underwent transurethral resection of bladder tumor. All patients had stage pTa or pT1 transitional cell carcinoma or carcinoma in situ without other concurrent malignancies. The patients were assigned to 3 treatment groups: control group--transurethral resection discontinued within the study, oral bacillus Calmette-Guerin (BCG) group--transurethral resection of bladder tumor plus BCG (Moreau) and intravesical BCG group--transurethral resection of bladder tumor plus BCG. Of 9 patients in the control group 8 (89%) experienced tumor recurrence during a mean followup of 20 months. Of the 28 patients in the oral BCG group 11 (39.3%) had recurrence during a mean followup of 36 months. Of the 34 patients in the intravesical group 6 (18%) had recurrence in a 24-month mean followup. The incidence of complications was higher in the intravesical (41.2%) than in the oral BCG group (28.5%). These results show that intravesical BCG is a more effective immunotherapy; however, oral BCG can be used in patients who do not accept intravesical BCG administration. 