Medical castration for advanced prostate cancer

Prostate cancer is an androgen-sensitive tumor. In the late stage, endocrine therapy is the main treatment, which is to reduce or eliminate the level of androgen in the body through surgery or medical castration.

Endocrine treatment can be performed by orchiectomy or medical castration. Medical castration is a subcutaneous injection of a luteinizing hormone-releasing hormone analog (LHRH-A) sustained-release agent once a month, which can achieve the effect of medical orchiectomy. LHRH-A is a synthetic luteinizing hormone-releasing hormone analog, which is 100 times more potent than the LHRH produced by the human body. After taking the drug, it can strongly stimulate the LHRH receptors in the anterior pituitary gland, causing its expression to be downregulated, reducing the surface receptors, and then reducing the pituitary gland's acceptance of LHRH stimulation, reducing the pituitary gland's secretion of luteinizing hormone (LH), and testosterone synthesis in the testicular Leydig cells, which eventually reduces the testosterone level to the castration level, so it is called medical castration. Medical castration can allow patients to avoid surgery, which meets the needs of some patients who want to retain their testicles due to appearance or psychological factors, and can be used for intermittent endocrine therapy. Therefore, the clinical application of LHRH-A to treat prostate cancer is gradually increasing.

LHRH-A can make the testosterone (T) in prostate cancer patients reach the castration level, and can significantly reduce the levels of FSH, LH, E2, and P. The castration effect is better than the surgical effect, because after surgical castration, the male sex hormone level decreases, causing a compensatory increase in androgens through negative feedback regulation of the central nervous system, while drug castration blocks the negative feedback effect of the central hypothalamus-pituitary-gonadal axis.