Information about Hormone Therapy and Surgical Castration
Male sex hormones (androgens)testosterone in particularare required to maintain the size and function of the prostate. As a result, a number of prostate cancer treatments are aimed at interfering with the effects of androgens. Blocking testosterone can temporarily cause the cancer to regress, or at least to grow more slowly. However, some prostate cancer cells are able to grow without testosterone.
These androgen-independent (or androgen-insensitive) cells enable the cancer to continue to grow even in the absence of testosterone. Therefore, although hormone therapy is useful in treating prostate cancer, it does not offer a cure.
Hormone therapy used to be reserved for men whose prostate cancer had spread to the lymph nodes, bone or other sites. Now it is often given preemptively to men whose cancer has not spread but is expected to. A rapidly rising PSA level in the months after treatment indicates a high risk of recurrence.
For men with advanced prostate cancer (spread beyond the prostate), the goals of hormone therapy are to prolong life and relieve symptoms such as bone pain or urinary tract problems. In general, men whose cancer has metastasized have the following survival times:
- 75 percent live less than five years
- 15 percent live five to 10 years
- 10 percent live more than 10 years
The survival duration for a man who chooses hormone therapy depends on the cellular composition of his prostate cancerthat is, the ratio of androgen-dependent cells to androgen-independent cells. The greater the number of androgen-dependent cells within the tumor, the more likely the cancer will respond to hormone therapy.
PSA level also helps predict treatment response. A PSA of less than 4 ng/mL within three to six months of initiating hormone therapy predicts a good response to the treatment. A rising PSA level during hormone therapy indicates that the disease is progressing.
No consensus exists concerning when hormone therapy should begin. Whether hormone treatment is started before or after cancer progression is documented on a bone scan may or may not affect how long a man survives. Moreover, all effective forms of hormone therapy have significant side effects. These side effects may include
- ED (which affects about 90 percent of men)
- loss of libido
- breast enlargement
- weight gain
- hot flashes
- loss of muscle mass
- osteoporosis (decreased bone mass)
- decline in cognitive function
Hormonal therapy also increases the risk of cardiovascular disease, and the harm may outweigh the benefit, especially for men with early localized cancer who are unlikely to experience improved cancer control when hormonal therapy is used in addition to other management options. Because no hormone treatment can cure the disease, regardless of when treatment begins, treatment side effects and the cost of hormone therapy must be given serious consideration when deciding when to start the treatment.
Hormone treatment can be accomplished in two ways. The first is through surgical castration (surgical removal of the testicles, which produce about 95 percent of a man's testosterone). The second approach is the use of medications that either interfere with the production of testosterone or block it from attaching to receptors inside cancer cells. These medications include
- luteinizing hormone-releasing hormone (LHRH) agonists, also known as gonadotropin-releasing hormone (GnRH) agonists
- LHRH antagonists, also known as GnRH receptor antagonists
Whether accomplished surgically or medically, hormone therapy prolongs the life of men with metastatic prostate cancer.
Surgical removal of the testicles, a procedure known as bilateral orchiectomy, is the easiest and oldest way to dampen testosterone's effects on prostate cancer cells. The operation can be performed in about 20 minutes under spinal or local anesthesia, and the man usually can go home the same day. Men who take anticoagulants, such as warfarin (Coumadin), may not be candidates for surgical castration because these medications place them at risk for uncontrolled bleeding.
Surgical castration involves making a small incision in the scrotum and removing each testicle. Neither the operation nor the recovery is painful. A variation of this procedure, called a subcapsular orchiectomy, removes only the contents of the testicles. The empty shell of each testicle is left in place, resulting in a more satisfactory outward appearance. Some surgeons do not use this technique because of the risk that some testosterone-producing cells may be left behind.
The effect of orchiectomy is almost immediate. Within 12 hours, testosterone levels plummet to what is known as the castrate range. Because orchiectomy is so effective, it is the standard to which all other hormone therapies are compared.
Even though surgical castration is the most effective and least expensive form of hormone therapy, only about a quarter of men choose to have the procedure. Psychological issues clearly influence the decision to have this operation, which cannot be reversed. Men who are psychologically troubled by the idea of orchiectomy can opt for medical castration. These treatments can be as effective as orchiectomy, and the side effects are similar.