Prostate cancer is one of the most common forms of cancer among men. The prostate gland is an integral part of the male reproductive system. It is responsible for secreting prostatic fluid, comprising about 30% of the male ejaculate. This fluid promotes motility, protection of genetic material, and longevity of sperm cells as they travel through the vagina.
It is estimated that 1 in every 7 men will be diagnosed with prostate cancer during their lifetime. Over 90% of prostate cancer diagnoses are in men over the age of 50, with an average age of 66. Although, a very serious disease, when caught early prostate cancer is treatable. In fact, the majority of men diagnosed will not die from prostate cancer. About 92% of prostate cancer is caught in its early stages. This is because men are encouraged to do yearly prostate cancer risk assessments, including both a digital rectal exam (DRE) and a blood screening for the prostatic specific antigen (PSA) level.
Neither the DRE or PSA level alone is enough to diagnose an individual with prostate cancer. The DRE is an exam done by the physician to palpate the prostate through the rectom and feel for solid nodules in the prostate. The PSA is known as a cancer marker, that is, when found above the normal range (below 4 ng/ml), there is an increased probability of that individual having prostate cancer. The only definitive test to determine if there are cancerous cells in the prostate is a biopsy. In a biopsy, small pieces of the prostate are removed and sent to the lab to be examined. The prostate tissues are examined under a microscope and rated based on how much they resemble regular cells. The lab uses what is known as a Gleason score. The higher the Gleason score, the farther the cells look from normal cells, and the more aggressive the cancer is likely to be.
When the cancer is slightly aggressive, it will most likely require treatment. There are several different treatment methods for prostate cancer, each with its own pros and cons. The two most common methods of treatment are radical prostatectomies, removing the prostate all together, and radiation, where high energy rays are used to kill the cancerous cells. However, not all prostate cancer needs to be treated right away. If an individual is asymptomatic and his biopsy reveals prostate cancer with a low Gleason score, the doctor may suggest to place him under active surveillance. This includes regular monitoring of the PSA and possible future biopsies. Although prostate cancer can be slow growing, the danger lies when untreated prostate cancer becomes metastatic. This occurs when cancer cells migrate from the prostate into the surrounding tissues by entering blood or lymph vessels. Cancer cells can find their way to many different places in the body including the bones. Upon diagnosis of prostate cancer, to determine if a patient’s cancer has metastasized, the physician will generally order both a CT scan, to examine with soft tissues, and a bone scan.
While there is no treatment that cures metastatic cancer, it can be managed. One of the methods used to manage metastatic prostate cancer is hormone therapy. The hormone Testosterone, and its derivative Dihydrotestosterone, promote growth, differentiation, and increase metabolism of prostate cells. By depriving them of these hormones, cancerous cell growth and activity in the tissues can be suppressed. Hormone deprivation can be achieved physically by surgical castration, since the testes are the main source of testosterone, or by chemical castration, using a class of drugs known as Gonadotropin releasing hormone (GnRH) agonists. These drugs act to decrease the testosterone produced by the testes by close to 90%. The decrease in cellular activity as a result of hormone deprivation can often be observed by monitoring the PSA. When hormone therapy is effective, there will generally be a decrease in the individuals PSA, which should be constant for the duration of the treatment.
Unfortunately, hormone deprivation is not always effective. When the individual’s PSA continues to rise despite extremely low levels of hormones, the treatment is most likely ineffective. This is considered to be castrate resistant prostate cancer (CRPC). Almost all individuals who are dying from prostate cancer at this time have CRPC. There is currently no cure or effective management for CRPC. The most common method used to try to treat CRPC is chemotherapy.
The treatment of prostate cancer has come a long way. It can oftentimes be treated with negligible effect on the individual’s quality of life. However, despite the low probability of death associated with prostate cancer, it is imperative that men ages 50-75 monitor their prostate cancer risk annually in order to best prevent late stage prostate cancer diagnoses.
Jean Paul Lamour Pre Medical Student at FIU contributed to this article
