Summary Fifteen post-menopausal patients with advanced breast cancer were treated with the LH-RH agonist leuprorelin (D-leu6-des-gly'0-Gn-RH-ethylamide) given in a dosage of 7.5 mg as a monthly subcutaneous depot injection, to assess the clinical activity and endocrine response (Stoll, 1979). More surprisingly, these agents have also been reputed to be effective in 16-20% of post-menopausal patients with advanced breast cancer (Harvey et al., 1981;Plowman et al., 1986). It has been suggested that response in this group may be due to a direct effect on the tumour, as some LH-RH agonists have been shown to have an inhibitory effect on breast cancer cells in vitro (Blankenstein et al., 1985;Miller et al., 1985), and LH-RH binding sites have been demonstrated in several breast cancer cell lines (Eidne et al., 1987).More recently, it has been shown that in post-menopausal breast cancer patients treated with an LH-RH agonist (goserelin), there was a significant reduction of serum testosterone levels, which was associated with a 22% fall in the level of serum oestradiol (Dowsett et al., 1988). It is therefore possible that the response of post-menopausal patients to treatment with LH-RH analogues may be due to decreased oestrogenic stimulation, rather than to a direct, inhibitory effect on the tumour.In this study, the clinical and endocrine response of 15 post-menopausal patients with advanced breast cancer was evaluated during their treatment with the LH-RH agonist leuprorelin (D-leu6-des-gly'0-Gn-RH-ethylamide) (Lederle Laboratories, Gosport, Hampshire, UK).
Patients and methodsFifteen post-menopausal women with locally advanced or metastatic, histologically proven breast cancer were entered into the study. Informed consent was obtained from all patients. Their mean age was 66 ± 7.6 years (mean ± s.d.), range 49-77, the mean weight was 68.5 ± 15.8 kg, range 50.1-108.5, and all patients were at least 2 years postmenopausal. Two tumours were oestrogen receptor (ER) Correspondence: M. Dowsett.