Goserelin is a medication used primarily in the treatment of certain hormone-sensitive conditions, including prostate cancer, breast cancer, and endometriosis. It belongs to a class of drugs known as gonadotropin-releasing hormone (GnRH) agonists.

Goserelin works by initially stimulating the production of hormones such as testosterone and estrogen. However, prolonged use of the medication results in desensitization of the pituitary gland, leading to a decrease in the production of these hormones. In conditions like prostate cancer, reducing testosterone levels can slow down the growth of cancer cells. In breast cancer, lowering estrogen levels can help to prevent the recurrence or spread of the cancer.