Unfortunately, once prostate cancer has spread beyond the prostate gland to other parts of the body, it is no longer curable. As such, the therapy or treatment is considered palliative. Therefore, early detection remains the key for ultimately improving survival from this disease. The treatment for metastatic prostate cancer (cancer which has gone from the prostate to other parts of the body) has not changed significantly since the 1940’s. Prostate cancer is stimulated to grow by the male hormone testosterone. By blocking testosterone, prostate cancer will go into remission (either stop growing, or at least grow more slowly). Eighty percent of men with metastatic prostate cancer will respond to hormonal therapy (blocking testosterone). The response is a temporary one due to the fact that the cancer will mutate (change) and begin to grow despite the absence of testosterone. Half of men treated with hormonal therapy will develop disease that no longer responds to hormone treatment within three years of instituting therapy.

Hormonal therapy to accomplish a reduction in blood testosterone level may be achieved surgically or medically. Removal of the testicles (surgical castration or bilateral orchiectomy) is a permanent form of testosterone therapy. The same effect can be achieved through the use of an injection given every three or four months. The medications are either Zoladex or Lupron. There is no difference in therapeutic efficacy between medical or surgical castration. Medical hormonal manipulation is reversible whereas orchiectomy is not. The presumed advantage to the non-surgical approach should be balanced against the need to see the physician every 3 months for the injection.

The timing of hormonal therapy has been debated for decades. When should androgen or testosterone withdrawal therapy begin? Should the treatment begin when metastatic disease is first detected or should it start only when the patient becomes symptomatic from the cancer spread (i.e.: bone pain, weight loss)? No study to date has demonstrated an overall, or cancer survival, advantage to early androgen therapy versus delayed therapy administered at the time of clinical or symptomatic spread. Early hormonal therapy will provide the patient with a longer interval free of progression of the cancer but, ultimately, there does not appear to be an actual survival advantage. While a longer interval free of cancer sounds advantageous, this benefit should be weighed against the side effect of androgen withdrawal. Hormonal therapy is not chemotherapy. As such, patients will not become nauseated, suffer from hair loss and loss of appetite. Patients on hormonal therapy will, however, suffer from hot flashes, loss of libido, impotence, experience fluid retention, muscle weakness and wasting and osteoporosis. The timing of hormonal therapy is dependent upon the clinical situation and the patient’s wishes.

Another approach is total androgen blockade. The testicles produce approximately 95% of the circulating testosterone levels. The remaining 5% is produced by the adrenal glands. Certain drugs(Casodex, Flutamide), known as antiandrogens, block the effect of the adrenal androgens. The role of the antiandrogen remains somewhat controversial. It is unclear whether combined standard androgen blockade (orchiectomy or Zoladex or Lupron) with antiandrogen therapy provides any therapeutic benefit or survival advantage. Whereas some studies have revealed that up to a six-month survival advantage can be achieved with combined hormonal therapy, other investigators have failed to duplicate these findings. The use of antiandrogens, which are taken orally, must be balanced against the expense of these medications and the side effects including liver dysfunction, breast tenderness, and GI intolerance. Drugs such as Zoladex and Lupron will initially stimulate testosterone production, leading to increased circulating blood levels. This can lead to a temporary worsening of symptoms. Placing patients on antiandrogens 14 days prior to starting the injection therapy can eliminate this flare response. No flare occurs after orchiectomy. Antiandrogens may also be used as second line hormonal therapy. Patients who are suffering from hormonal resistant cancer (treated by LHRH agonist or orchiectomy) may then be placed on antiandrogens. Up to 50% of these patients will experience a temporary remission. Patients on long-term total androgen ablation who develop hormonally resistant disease with evidence of progression may also experience a temporary remission by stopping the antiandrogen. This is known as the antiandrogen withdrawal phenomenon. This response is experienced by only a minority of the patients and is short-lived.

Radiation | Surgery | Prognostic Indicators | Therapy for Localized Prostate Cancer