Remission of postmenopausal breast cancer during treatment with the luteinising hormone releasing hormone agonist ICI 118630.

Ten previously untreated postmenopausal women with metastatic breast cancer, none of whom had received prior systemic therapy, were treated with the luteinising hormone releasing hormone (LHRH) analogue D-Ser(But)6, Azgly10-LHRH (ICI 118630). Two obtained an objective partial remission, one in bone metastases and one in lung metastases. One patient proved unassessable. Amongst the seven failures, incomplete pituitary gonadotrophin suppression over the relatively short treatment period with the daily injections was noted. The seven patients failing ICI 118630 received tamoxifen and two with high tumour oestrogen receptor values responded. LHRH analogues may provide a novel endocrine therapy for postmenopausal breast cancer although more data are needed. In this study, the monthly depot injection proved superior to daily injections with regard to gonadotrophin suppression, although it is not clear that this provides the mechanism of action.