Androgen deprivation therapy (ADT)

GnRH agonists (leuprolide, goserelin) and antagonists (degarelix, oral relugolix) lower testosterone to castrate levels; bilateral orchiectomy does the same permanently. ADT is combined with radiotherapy for intermediate- and high-risk localised disease (4-6 months to 2-3 years), and with ARPIs and sometimes docetaxel in metastatic hormone-sensitive disease. Side effects are hot flushes, fatigue, loss of muscle and bone, weight gain, sexual dysfunction and metabolic and cardiovascular risk, hence interest in intermittent schedules and in whether metastasis-directed therapy can postpone it. Endocrine therapy in breast cancer is the analogous concept for oestrogen.