Irosustat is primarily used in the treatment of hormone-dependent cancers, particularly breast cancer. It functions as a steroid sulfatase inhibitor, which helps in reducing the production of estrogen, a hormone that can promote the growth of certain types of cancer cells. By blocking this enzyme, Irosustat effectively lowers estrogen levels, thereby slowing down or inhibiting the progression of cancer. It is often considered in cases where other hormonal therapies have not been effective, offering an alternative approach to managing the disease. Additionally, its application is being explored in other estrogen-related conditions, expanding its potential therapeutic uses.