Abstract
Experiment I was conducted to examine the optimum duration of N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) for studying promoters and inhibitors of mouse bladder carcinogenesis in mice. When the mice were treated with 0.05% BBN for 12 weeks and subsequently observed without any treatment until the 28th week, the incidence of CIS and invasive carcinoma were 20-80% and 20-60%, respectively. These results suggest that an experiment involving 12-week treatment with 0.05%BBN is useful in exploring inhibitors. Using this model, the effects of three regimens of combination chemotherapy (CAP, M-VAC, and MEC regimens) in supressing the development of bladder carcinoma were examined in Experiments 2 and 3. The animals treated with CAP or MEC had significantly lower incidences of invasive carcinoma than BBN alone groups. As for M-VAC treated group, the incidence of superficial bladder carcinoma was significantly lower than BBN alone group. Thus each of the three combination chemotherapy regimens suppressed the development of mouse bladder carcinomas. These results suggest that CAP, M-VAC, and MEC regimens are useful in adjuvant chemotherapy for invasive bladder carcinoma.
