Hormonal therapy for cancer

Hormone therapy is an extremely effective and relatively non-toxic therapy for both breast and prostate cancer; some other cancers demonstrate minor levels of hormone sensitivity. Serum concentrations of oestradiol and testosterone are controlled by the hypothalamic–pituitary–gonadal pathway. In premenopausal women, oestradiol is produced primarily from the ovaries, whereas in postmenopausal women peripheral conversion of adrenal androgens by aromatase within peripheral fat predominates. In premenopausal women with breast cancer and men with prostate cancer, hormonal therapy is primarily achieved by castration. In postmenopausal women, selective oestrogen receptor modulators (e.g. tamoxifen) or aromatase inhibitors are used. Hormone therapy is often part of curative therapy, either neoadjuvantly (to reduce the size of the primary cancer prior to radical surgery or radiotherapy), or adjuvantly (to reduce the risk of recurrence). Hormone therapy is also highly effective in patients with incurable locally advanced or metastatic disease. The majority of patients respond, often with a prolonged period before there is evidence of relapse. Unfortunately, most patients do eventually relapse. However, there are increasing numbers of active and relatively non-toxic agents entering clinical practice or clinical trials in this ‘castration-resistant’ setting.