Most prostate cancer patients are initially effective on depot or combined androgen blockade therapy, but after a period of time, almost all patients will progress to hormone-independent prostate cancer. Intermittent endocrine therapy (IET) is an endocrine therapy in which the drug is first deprotonated, then stopped when the criteria for stopping the drug are met, and then re-administered after a period of stopping the drug. The rationale is that prostate cancer cells that are able to survive under low androgen levels continue to grow by acquiring anti-apoptotic potential through supplemental androgens, which can prolong tumor progression to the hormone-independent stage without major negative effects on lesion progression or survival time. In addition, the advantages of intermittent endocrine therapy include improved quality of life for patients and reduced treatment costs.