The effect of combination chemotherapy on ovarian, hypothalamic and pituitary function in patients with breast cancer.

Treatment of breast cancer by combination therapy induced luteal insufficiency, anovulatory cycles and sometimes hypergonadotropic amenorrhea in premenopausal women with previously normal mentrual cycles and ovarian function. In chemotherapy induced amenorrhea 17 beta-estradiol levels were those found in ovarectomised or postmenopausal women. Chemotherapy affected the ovary itself and not the hypothalamus or pituitary, the negative feedback mechanisms remaining intact. The ovary of perimenopausal patients was much more sensitive to cytotoxic drugs; following a short time chemotherapy hypergonadotropic amenorrhea invariably developed and the ovary seemed to be again the prime site of action. Postmenopausal patients continued to have physiologically high LH and FSH plasma concentrations and low plasma levels of prolactin and 17 beta-estradiol under cytotoxic treatment.