Rapid induction of carcinoma in situ in dog urinary bladder by sequential treatment with N-methyl-N'-nitrosourea and N-butyl-N-(4-hydroxybutyl)-nitrosamine.

A highly atypical intraepithelial proliferation, which was interpreted as carcinoma in situ, developed in the urinary bladder of 2 beagle dogs after repeated intravesical instillations of N-methyl-N'-nitrosourea followed by oral administration of N-butyl-N-(4-hydroxybutyl)nitrosamine. The latent period was 37 weeks. The technique may provide a useful model to study the natural history of bladder cancer, particularly carcinoma in situ.