New agents for chemoprevention of prostate cancer.

The magnitude of the problem of prostate cancer, and the failure of conventional chemotherapy and surgery to effect a marked diminution in the total number of deaths from this disease, now indicate that chemoprevention of prostatic carcinogenesis must be seriously considered. We describe the development of a new system for quantitating the process of prostatic carcinogenesis in an experimental animal, and the use of this system to demonstrate that the retinoid, 4-hydroxyphenylretinamide, the deltanoid, Ro24-5531, and the estrogen analog, tamoxifen, all are effective agents for prevention of experimental prostate cancer.