Effect of adrenalectomy, flutamide, and leuprolide on the growth of the Dunning rat R-3327 prostatic carcinoma.

The R-3327 prostatic tumor implanted in the male Copenhagen x Fischer F1 rat continues to grow because androgen is being supplied from an endogenous source. It follows that regimens which decrease the availability of androgen will retard the growth rate of the tumor. These experiments showed that castration, the antiandrogen flutamide, and the luteinizing hormone-releasing hormone (LHRH) agonist leuprolide inhibited tumor growth. Adrenalectomy alone had no significant effect on tumor size and did not further retard the growth of the tumor in castrated rats. Further, under the conditions of this study, there was no significant difference in tumor growth rates between the groups of rats treated with either flutamide alone or flutamide combined with leuprolide. Total ablation of androgen may not be needed for maximal inhibition of tumor growth.