As soon as the efficacy of the endocrine management of carcinoma of the prostate, whether by orchiectomy, the administration of estrogens or a combination of the two had been established by numerous observers, chiefly through the fundamental investigations of Herbst1and of Huggins,2carefully compiled studies soon became available concerning the extent of regression of the primary neoplasm and its metastases following the various types of therapy. From extensive reviews of statistics to date, as well as from experience gained in treating 200 patients with prostatic cancer at the Brady Urological Institute by the administration of diethylstilbestrol, we have come to expect objective regression of the primary growth in approximately 75 per cent of the cases and of its metastases in approximately 45 per cent. In our clinic we have found it advantageous to classify cases of prostatic carcinoma into four main groups: I. Early, in which the