Prostate cancer is one of the most common forms of cancer in the United States. Over the past twenty years, there have been significant changes in the way physicians screen and treat this disease. This paper will address common screening modalities, the effect of age and ethnicity on this disease, and its non-surgical treatment options.
In the United States, there are three primary methods to screen for prostate cancer, prostate-specific antigen (PSA), a digital rectal exam, and a prostate biopsy. PSA is a glycoprotein that is released by the prostate. It is believed that when cancer disrupts the prostatic capsule, PSA is released. Blood tests would be able to detect the levels of this antigen. PSA measurements were once thought to be a breakthrough in the diagnosis of prostate cancer. However, studies have shown that the positive predictive value of this exam is small by comparison, and there is not much absolute risk reduction of diagnosis (Schroder, et al. 2000). Another method to screen for prostate cancer is a digital rectal exam (DRE). A physician can reach the and feel for any hard nodule, asymmetry, or indurations. If either the PSA or a DRE is positive, then the patient should have a biopsy to confirm suspicions. Tissue samples are taken from the prostate and analyzed for evidence of cancerous cells. A biopsy is considered the gold standard for prostate cancer screening. Due to the recent controversy of prostate cancer screening, there is no current consensus on recommendations for prostate cancer screening. Many medical societies are saying that patients should have a discussion with their physician about the risks and benefits of screening and come up with a plan that will balance the risks and benefits.
While it is beneficial to screen patients for prostate cancer, it is no longer a required that all males to be tested for this disease. Because there is no mandatory screening, it is important to identify individual risk factors for prostate cancer. Age and ethnicity are the two most common predisposing factors to developing prostate cancer, studies have shown that there is a low incidence of clinically diagnosed prostate cancer before the age of forty, but the risk increases rapidly from fifty to seventy years of age (Hankey et al., 1999). Another important risk factor is ethnicity. Studies show that African-Americans have a higher chance of developing prostate cancer and possess an earlier age of onset than other ethnicities (Parker, et al., 2011). Diet, hormone levels, and genetic factors can also determine the risk of prostate cancer but are not as useful as age and ethnicity.
There are several treatment modalities for patients with prostate cancer, including surgery, chemotherapy, and medical management. Treatment depends on the severity and the location of the prostate cancer. For individual patients with advanced cancer with a castration-sensitive tumor, they will benefit from pharmacological management via androgen deprivation therapy. The theory behind this treatment is that prostate cancer use testosterone to grow and by inhibiting testosterone, the prostate and tumor will shrink. There are two classes of drugs that can achieve this effect, antiandrogens, and GnRH antagonists. Antiandrogens will competitively bind to the androgen receptor and block its interaction with testosterone and dihydrotestosterone. This medication will not affect the level of testosterone in the body or affect the hypothalamic-pituitary axis. The second class of drugs are GnRH inhibitors. These drugs act on the pituitary gland and block the release of LH and FSH, two hormones that would signal the production of testosterone or dihydrotestosterone. There are several long and short-term effects of the medical treatment of prostate cancer. Many of these symptoms stem from the lack of testosterone in the body. In the short term, patients can have loss of energy and hot flashes. Long-term effects of anti-hormonal therapy is the loss of libido, osteoporosis, gynecomastia, cardiovascular disease, decreased muscle mass.
Prostate cancer is a disease that affects many people each year. It is known that the risk of developing cancer of the prostate increases as men age or if they are African-American. There have been recent changes in the recommendations for the use of screening measures such as DRE and PSA levels. Regarding treatment, medical anti-hormonal therapy can be used in advanced cases. Scientists are continuing to research this disease to find better screening tools and treatment modalities to prevent instances of prostate cancer and to cure patients who have been diagnosed with the disease.
References
Hankey, B.F., et al. (1999) Cancer surveillance series: interpreting trends in prostate cancer--part I: Evidence of the effects of screening in recent prostate cancer incidence, mortality, and survival rates. Journal of the National Cancer Institute, 91(12):1017-1024. Retrieved from http://dx.doi.org/10.1093/jnci/91.12.1017
Parker, P.M., (2011) Prostate cancer in men less than the age of 50: a comparison of race and outcomes. Urology, 78(1):110-115. Retrieved from http://dx.doi.org/10.1016/j.urology.2010.12.046
Schröder F.H., et al. (2000) Prostate cancer detection at low prostate specific antigen. Journal of Urology, 163(3):806-812. Retrieved from http://dx.doi.org/10.1016/S0022-5347(05)67809-3
