The prostate is separated into four lobes: anterior, posterior, lateral, and median. The anterior lobe, or isthmus, lies anterior to the urethra. It is mainly fibromuscular and contains very little glandular tissue. The posterior lobe lies posterior to the urethra and inferior to the ejaculatory ducts. This is the lobe palpated during the digital rectal examination. The prostate is best examined when the bladder is full which provides adequate pressure to hold the prostate in place. The lateral lobes lie on either side of the urethra and are a large portion of the prostate. The median, or middle, lobe lies between the urethra and the ejaculatory ducts.
The main arterial supply to the prostate is the prostatic arteries, which are main branches of the internal iliac arteries. The venous drainage is the prostatic venous plexus.
PATHOLOGY OF THE PROSTATE
There can be many problems associated with the prostate. One of the problems is Hypertrophy of the Prostate, which is an enlargement of the prostate and is common after middle age. The prostate projects into the urinary bladder and impedes urination by distorting the urethra. If the median lobe enlarges enough the urethral orifice can be obstructed. This may cause the man to feel as if he has to empty his bladder and when he can't it may cause him to strain, which further obstructs the orifice.
The disease heard about most often in association with the prostate is Prostate Cancer. This disease is common in men older than 55. It is the second leading cancer killer in men. According to the American Cancer Society, this year approximately 39,000 men will die of this disease and 184,500 new cases of prostate cancer will be diagnosed. Also, African-American men are two times more likely to develop prostate cancer than Caucasian men.
Prostate cancer is a malignant transformation and growth of the glandular portion of the prostate. The tumor can then spread into the seminal vesicles, glands located next to the prostate and below the bladder, or to the lymph nodes, which filters clear fluid draining from the prostate. The bone is the most common distant site of metastases.
There are two methods in which to detect prostate cancer. The first method of detection is the digital rectal exam. A physician inserts a gloved finger into the anus and digitally palpates the posterior lobe of the prostate. If the prostate feels hard and irregular it is a good indication that there is something wrong. The second method of detection is by measuring the PSA, or prostate specific antigen. The PSA is an enzyme that is released into the blood by both normal and cancerous prostate cells, but is elevated when there is disease present. Any condition that could cause injury to the prostate can cause elevation of the PSA, however, the possibility of cancer is increased with a PSA above 4.0 ng/ml. The patient must have a blood test in order to check the PSA level.
TREATMENT OPTIONS FOR PROSTATE CANCER
There are several forms of treatment available for a prostate cancer patient, depending on the prognosis. For example, the most common treatment offered to patients with localized prostate cancer and a 10-year or greater life expectancy is radical prostatectomy. This is a surgical operation designed to remove the prostate, seminal vesicles, and many times the lymph nodes.
Another treatment option is external-beam radiation therapy. This is designed to deliver irradiation from outside the body to the prostate in order to destroy the tumor. This series is an option for those patients deemed noncandidates for surgery. Many patients may choose radiation therapy to avoid the side effects and morbidity of radical prostatectomy.
A different treatment option is interstitial radioactive seed implants (bracytherapy). This is designed to deliver irradiation from radioactive seeds placed directly into the prostate. It is best suited for localized prostate cancer. It is a monotherapy and is quite attractive to those patients wanting a single and safe outpatient procedure, which has less of a risk of incontinence and impotence than surgery.
There are also treatment options available to those patients with clinically advanced prostate cancer. For example, hormone ablation therapy involves medical or surgical castration and is commonly applied to either locally advanced or metastatic prostate cancer. However, recent studies do not reveal a survival advantage of any effective androgen ablation treatment regimen.
The difficult decision on treatment faced by patients with clinically localized prostate cancer involves many factors. The patient's quality of life and life expectancy, ignoring the fact that they have prostate cancer, need to be addressed. Also, the patient must decide which treatment option will allow them the quality of life that they expect for the future.
It has been discovered that a certain herpes gene may help fight prostate cancer, according to the first study to demonstrate that gene therapy is safe and active against this disease. This trial examined 18 patients who had local recurrence of prostate cancer following initial treatment with radiation.
The herpes gene, thymidine kinase, activates a normally inactive antiviral drug called ganciclovir. Human cells do not normally contain this gene and are therefore resistant to ganciclovir's effects. When the gene was successfully transferred into prostate cancer cells, the ganciclovir was activated. This resulted in the death of the cancerous cells.
This study was designed only to assess safety and study different dosing levels. Three patients in the study showed a significant decrease in PSA levels. This is an indication that the tumor may be diminishing in size. One patient was cancer free after biopsy.
Another study identified a genetic mutation in the prostate cancer gene. According to scientists at the University of Pennsylvania Cancer Center, this is the first time that the mutation has been located and men who carry this mutation in the CYP3A4 gene had a more advanced prostate tumor than those without the mutation. These results suggest that the gene is involved in prostate cancer. The gene is believed to be associated with the commonly occurring variety of prostate cancer in the general population, not the hereditary disease. Further testing will determine if a mutated CYP3A4 directly causes prostate cancer.
Prostate cancer is a very real threat to older men. In order to catch it in time, men should start having PSA drawn at the age of 40. This should insure an early diagnosis and a healthy prognosis.