The Zoladex implant is injected under the skin of the abdomen, from where it steadily releases the goserelin into the bloodstream over a four week period. An implant is injected every 28 days. It is used for : Prostate cancer, Breast cancer, Endometriosis, Thinning the lining of the womb (endometrium) prior to surgery (endometrial ablation or resection). Fibroids of the uterus (prior to surgery, in combination with iron in women who are anaemic). Preparing the pituitary gland before treatment with gonadotrophins to stimulate ovulation in fertility treatment (IVF).