Most patients with hormone-dependent prostate cancer have cancer cells that die in the absence of androgen stimulation, and endocrine therapy is to inhibit the stimulating effect of androgens on prostate cancer cells. Endocrine therapy is mainly through the following strategies: ① Inhibit androgen production: 70% to 80% of androgens in human body originate from male testes, and the other 20% or so originate from human adrenal glands, which can be removed by surgical removal of both testes or pharmacological depot (using the method of injection to achieve the same purpose as surgical removal of both testes); ② Inhibit androgens on prostate cancer cells: about 20% of androgens originate from human adrenal glands, anti-androgen drugs can be used to inhibit the stimulating effect of androgens on prostate cancer cells, and these drugs are usually taken orally. 1.Depot treatment ①Surgical depot: i.e. bilateral orchiectomy, surgical depot can make androgens fall rapidly and continuously to very low levels (depot level), the effect is exact, and the surgery is less traumatic, most of the elderly patients can tolerate this surgery. Compared with drug depot, another advantage of surgical depot is its low cost, which is suitable for China’s national conditions. ②Denervation by drugs: A drug called “luteinizing hormone releasing hormone analogue” is injected to achieve the same purpose as removing the testicles. This drug is currently available in the market: Goserelin (Norad), leuprolide (Inhibiton), Treprostin (Daphylline). These drugs are usually injected once a month, and there are now also dosage forms that are injected once every 3 months. After the first injection of the drug, androgen levels gradually increase, reaching a peak at 1 week (transient increase in androgens), and then gradually decrease, reaching a depot level (the same level as that of testicular removal) by 3 to 4 weeks, but about 10% of patients do not reach the depot level of androgens. Compared to surgical debridement, drug debridement is more expensive (about RMB 2,000 per month), and drug debridement is one of the standard methods of androgen removal treatment and is widely used in Europe and the United States. Since a transient increase in androgen levels occurs with the initial injection, anti-androgen drugs should be given for two weeks starting on the day of injection to counteract the exacerbation of the disease caused by the transient increase in testosterone. For patients with bone metastases and spinal cord compression, drug debridement should be used with caution, and surgical debridement with rapid reduction of testosterone levels is an option. (iii) Estrogen: The most common estrogen is hexestrol. Daily oral administration of hexestrol lmg, 3mg, or 5mg can achieve the same effect as surgical or pharmacological denervation, but the cardiovascular side effects are significantly increased, therefore, caution should be exercised in its application. 2.Maximal androgen blockade therapy The aim is to remove or block both testicular-derived and adrenal-derived androgens. The commonly used method is depot treatment combined with anti-androgen drugs. There are two major categories of anti-androgen drugs: one is steroids, represented by megestrol acetate; the other is non-steroidal drugs, mainly bicalutamide and flutamide. The combination of maximum androgen blockade therapy with non-steroidal anti-androgen drugs can prolong the overall survival by 3-6 months compared with depot alone. 3. Intermittent endocrine therapy Patients are given endocrine therapy for a period of time so that the disease is controlled and PSA drops to a certain level and is maintained for a period of time, then the drugs are discontinued and observed, and the PSA is treated with drugs again when it rises to a certain level. The advantages of intermittent endocrine therapy are mainly to improve patients’ quality of life and reduce the cost of treatment. Clinical studies have shown that patients’ quality of life is significantly improved during off-treatment period, such as libido and physical strength recovery. Most of the intermittent endocrine therapy medications are used for maximum androgen blockade therapy, where the depot method is drug depot (if bilateral orchiectomy is done, intermittent endocrine therapy cannot be done). The criteria for stopping intermittent endocrine therapy are not uniform, and the recommended discontinuation criteria in China is after PSA ≤ 0.2ng/dl for 3-6 months. The criteria for restarting treatment are also not uniform, and the current domestic recommendation is to start a new round of treatment when PSA>4ng/d1.