[GnRH agonists and breast pathology]

The discovery of hormone receptors and tamoxifen has revolutionized the management of breast cancer in women as the existence of oestrogen receptors has improved the response rate to hormone treatment from 30 to 50-70% with a further increase in this efficacy if there are also progesterone-positive receptors. LH-RH analogs induce medical castration. Their efficacy in combination with tamoxifen was demonstrated in terms of survival in pre-menopausal women with metastatic cancer. In the adjuvant situation, a meta-analysis of the 1980s demonstrated a benefit in terms of survival without relapse confirmed by more recent studies showing a reduction in the relative risk of relapse. On radiotherapy or ovariectomy, which are radical treatments, medical castration with LH-RH agonist analogs in combination with tamoxifen is therefore an alternative, reversible therapy for outpatients in particular now that a possible direct anti-tumor effect has been suggested by in vitro studies. Nevertheless, at present in France, Marketing Authorisation has not yet been granted for metastatic cancer.