Experimental and clinical study of intravesical BCG therapy. The role in the prevention of recurrence of superficial bladder tumor

Abstract

The effects of Tokyo strain bacillus Calmette-Guerin (BCG), which is available in Japan for treatment, were studied in an experimental murine bladder tumor (MBT-2) model prior to clinical study for treatment of superficial bladder tumor. The results were as follows: Tokyo-strain BCG is more effective on the local injection around the tumor than on systemic administration. BCG therapy is more effective at earlier time of small tumor burden. BCG also has a prophylactic effect against the tumor growth. Clinical trial of intravesical instillation of BCG was performed on patients with superficial bladder tumor for prophylaxis of tumor recurrence after transurethral resection of the tumor. In patients of 145 primary cases, the tumor recurrence rate after BCG therapy was estimated, comparing with that of historical control in our department. The historical control groups are consisted of 50 patients who were treated by some intravesical chemotherapy after TUR and 38 patients, who were treated by TUR alone. The tumor recurrence rate in BCG group was significantly lower than that in both control groups. No relationship between PPD responsiveness and the tumor recurrence rate could be detected. On the other hand, in the patients of 36 recurrent cases, evaluation was performed by the tumor recurrence rate comparing with those during the two years prior to BCG therapy. The results demonstrated a statistically significant decrease in recurrent tumor following BCG therapy. Although most of the adverse effects in this study such as bladder irritability, flu-like syndrome and macroscopic hematuria were minimal and tolerable. There were no significant side effects or serious complications attributable to BCG therapy in this series. These results indicate that intravesical Tokyo strain BCG instillation provide prophylactic effects against recurrence of superficial bladder cancer.