The significance of bacillus Calmette-Guerin in the therapy of carcinoma in situ of the bladder

We treated ten patients with carcinoma in situ of the bladder (primary type, 6 and secondary type, 4) by intravesical bacillus Calmette-Guerin therapy. All patients received 8 weekly instillation, and among them 3 patients were followed by additional instillation monthly for 7 months. Complete regression (negative biopsies and cytology study) was observed after 8 weekly instillation in all patients. To elucidate the mechanism of action of BCG on carcinoma in situ, the biopsied specimens after BCG instillation were examined light and electronmicroscopically. It was speculated that BCG might act on cancer cells in two ways: one was sloughing and denudation of the cancer cells by acute tuberculous cystitis, and the other was a role of the macrophages through immune reaction. In our study, the toxicity and complications seemed to be much severer than previously reported. Vesicoureteral reflux was observed in 6 patients. Decreased bladder capacity noted in all patients, among them radical cystectomy and colocystoplasty were performed in 2 patients under the diagnosis of bladder contracture. Although complete regression was observed in all patients after 8 weekly BCG instillation, the duration being free from cancer cells was variable. And we also discussed on the additional therapy in such patients in the literature.