Hypothalamic-Pituitary-Ovarian Axis in Women with Operable Breast Cancer Treated with Adjuvant CMF and Tamoxifen

The effect of adjuvant CMF (cyclophopshamide, methotrexate, and 5-fluorouracil) and tamoxifen (TM) on hypothalamic-pituitary-ovarian function was studied in 120 women with stage I-II operable breast cancer. Sixty patients were premenopausal, of whom 25 were treated with CMF for 9 cycles, 25 with CMF for 9 cycles + TM for 2 years, started concurrently, and 10 with TM alone for 2 years. Sixty patients were postmenopausal and they were all treated with TM alone for 2 years. In all groups treatment was started within 4 weeks of mastectomy. Plasma levels of estrone (E1), estradiol-17β (E2), follicle-stimulating hormone, luteinizing hormone (LH), prolactin (Prl), testosterone (T) and thyroid-stimulating hormone (TSH) were determined in all patients before surgery and again at 3-month intervals from initiation of the adjuvant therapy. In ten patients of each treatment group FSH-LH and Prl-TSH release was determined following stimulation with releasing hormones. CMF and CMF + TM therapy resulted in amenorrhea in 42/50 premenopausal patients with decrease of E1 + E2 (p < 0.001) and elevation of FSH (p < 0.001) and LH (p < 0.01) plasma concentration to postmenopausal levels. In premenopausal women treated with TM a marked increase of E1 + E2 (p < 0.001) was observed with unaltered FSH-LH plasma concentration. A significant fall of Prl also occurred in these patients. In postmenopausal women and premenopausal patients with CMF-induced amenorrhea TM produced a marked fall of FSH-LH and a decrease of Prl plasma level. Plasma TSH and T were not affected in any patient by any of the treatment regimens. The results of the stimulatory tests are in agreement with the hormonal changes observed under basal conditions and indicate that, whereas CMF suppresses the ovary and does not alter hypothalamic-pituitary function, TM induces profound changes of the hypothalamic-pituitary-ovarian axis.