The male hormone testosterone, which stimulates prostate growth during a man's adolescent years, will stimulate prostate cancer to grow as well. Hormone therapy either blocks or removes testosterone from the body to temporarily slow or stop cancer growth. Hormone therapy can be used at all stages of cancer growth either alone or with other types of therapy.
However, after a while, cancer cells will mutate beyond the need for testosterone and will begin to spread again. This is called "androgen independent" or "androgen resistant." The lack of testosterone can also produce male menopause, which has similar side effects to female menopause: hot flashes, fatigue, anemia, breast growth or tenderness, moodiness, weight gain, impotence, loss of interest in sex, loss of lean muscle mass and strength, loss of body hair, loss of bone density, and loss of testicular and penile volume. Some of these symptoms can be treated, and some men will experience only a few or none of the symptoms.
Hormone therapy is done through use of medications or by surgically removing the testicles, also called orchiectomy ("orkee-ek-toh-mee"). Hormone therapy can consist of shots every one to four months or taking pills daily. Hormone therapy from medication lasts only as long as the medication is administered. Once stopped, testosterone production typically resumes normal levels, and the male menopause symptoms will go away. The surgical procedure causes testosterone levels in the body to effectively lower almost immediately. An orchiectomy is a permanent treatment and is sometimes used with medication if testosterone production needs to be lowered even more.