Francisco Garcia-Moreno, M.D.

For an organ the size of a walnut, the prostate sure can cause a lot of trouble. It is the most common type of cancer in men, although as a cause of death, it ranks behind lung cancer and colorectal cancer.

The prostate is a gland which has evolved in the lower pelvis to aid reproduction. It is comprised of hormone sensitive tissue and as a result, tends to be sensitive to hormonal manipulation. Another important characteristic of the prostate is that it produces PSA (Prostate Specific Antigen) that helps keep semen in its liquid form. In effect, PSA has become a useful marker for the diagnosis and the management of prostate cancer.

We can screen for prostate cancer with a Digital Rectal Exam (DRE) and a serum PSA level. As with any screening test, these tests are far from perfect. False positives (a test is positive when their is no disease) may be a bigger issue than false negatives (test is negative when there is disease), leading to biopsies and perhaps therapy in patients who should never receive treatment. This can occur in older men (over 70 years of age) and in other men in whom the disease is simply not aggressive.

Therapy for localized disease is either surgery or radiation.  A recent study published in the New England Journal of Medicine suggests that patients who receive hormonal therapy along with radiation therapy have an increased overall survival. Localized disease can usually be cured.

If the patient develops metastatic disease, the first line of therapy is hormonal manipulation. Simply put, we are seeking to achieve Androgen Deprivation (reducing the concentration of testosterone). This can be done surgically, by way of a bilateral orchiectomy (removal of the testis), or through the use of medication. In the latter case, we can suppress the production of luteinizing hormone (the hormone that causes the testis to produce testosterone). The most commonly used medications are GnRH Agonists (examples are leuprolide and goserin). Antiandrogens (bicalutamide) bind to androgen receptors and block testosterone from binding to there targets. This can be useful in controlling the effects of the 5-10% of total testosterone that is not produced in the testes (testosterone is also produced by the adrenal glands). The use of a GnRH Agonist in combination with Androgen Deprivation results in Complete Androgen Blockade.

It is important to note that all these therapies are palliative in nature. If they should eventually fail, we can attempt a second-line and even third-line hormonal therapies, but each successive attempt is much less likely to work. If that is the case, consideration can be given to a handful of chemotherapy agents that have a proven beneficial in treating this disease. The key continues to be early detection as well as the determination of which patients actually need to be treated.