Historical perspective

T HAS LONG BEEN RECOGNIZED that some human I breast cancers are "hormone-dependent'' in that their growth depends on a continued supply of female sex hormones. A relationship between ovarian secretions and the growth of some human breast cancers was suggested as early as 1836, when Cooper4 observed fluctuations in tumor proliferation during different phases of the menstrual cycle. Direct evidence for supporting factors of ovarian origin was provided in 1896, when Beatson,2 with remarkable insight for that time, removed the ovaries from young women with advanced breast cancer and reported that some patients showed striking regression of their metastatic lesions. In 1941, the introduction of orchiectomy for the treatment of prostatic cancer12 revived interest in Beatson's observations, and ovarian ablation by oophorectomy or by radiation castration became a generally accepted primary therapy for advanced breast cancer in premenopausal women.