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The Prostate |
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The prostate is a walnut shaped organ located just below the bladder in
males. It is believed that the function of the prostate is to modify or
activate sperm and supply ingredients to semen before ejaculation. The
urethra passes through the prostate as it exits the bladder and enters the
base of the penis. Consequently, enlargement of the prostate can lead to
compression of the urethra and the symptoms associated with prostatic hyperplasia.
Benign Prostatic Hyperplasia
Benign prostatic hyperplasia is a nonmalignant enlargement of the prostate
and is the most common benign tumor in males, requiring 1.7 million physician
office visits each year and results in more than 300,000 prostatectomies.
The prostate weighs only a few grams at birth but undergoes two different
growth cycles during the lifespan of the average male. First at puberty the
prostate undergoes androgen-mediated growth and reaches approximately 20g by age
20. It remains this size until about the fifth decade of life when it
undergoes a second increase in size in the majority of males. BPH will
affect men starting in their forties and will increase so that by the time men
are in their seventies, 90% will have some degree of prostatic hyperplasia.
Etiology
The exact cause of prostatic hyperplasia is not known. However, two clear criteria necessary for the occurrence of prostatic hyperplasia are an
increase in age and the presence of testes. The androgen that mediates the
growth of the prostate at all ages is dihydrotestosterone (DHT), which is formed
within the prostate from plasma testosterone. Studies performed on dogs have
shown that increased levels of DHT within the prostate lead to a direct increase
in size. Secondly, as men age the production of estradiol increases in relation
to other androgens. It has been found in animal models that estrogen may work in
a synergistic manner with DHT to induce prostatic hyperplasia.
Symptoms
The symptoms of BPH are those associated with obstruction or irritation of
the posterior urethra. These symptoms may include frequency, nocturia, dysuria ,
hesitancy in initiating voiding, dribbling after voiding, diminution of the
caliber and force of the urinary stream, the sensation of incomplete emptying,
and finally urinary retention. Early on in the disorder the symptoms may be
minimal due to the compensatory effect of the musculature of the bladder.
However, as the disorder progresses symptoms will worsen.
Diagnosis
The initial evaluation of a patient with these symptoms should include a
detailed history focusing on the urinary tract. Symptoms may also be quantified
with the use of the AUA
Symptom Index. A digital rectal exam should also be performed at
this time for characterization of the size, consistency, and shape of the
gland. It should be noted that the size of the prostate does not always
correlate with obstruction of the urethra and often a seemingly small prostate
can produce symptomatic obstruction.
There are a variety of tests available to the practitioner in the evaluation
of prostatic hyperplasia. It should be noted however that although these tests
may help to quantify a patient's condition they are often not indicative
of symptoms. For example, in a recent study comparing saw palmetto vs. placebo, those
patients who reported symptomatic relief had no statistical change in their
objective measure of urinary tract performance.
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Prostate Specific Antigen (PSA)
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Will help differentiate between BPH and cancer of the
prostate. However, it should be noted that a PSA will not differentiate
between BPH and early prostatic cancer. |
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Uroflowmetry |
May help identify patients with normal urinary flow that may
not require intervention. |
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Post-void Residual Urine Volume |
Will help identify patients who may need more aggressive
therapy. |
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Pressure Flow Studies |
Identify patients with primary bladder dysfunction. |
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Treatment
Current treatment strategies for BPH are dependent on the severity of the
patient's symptoms. Patients with mild disease benefit most from conservative
monitoring. If symptoms progress, patients may receive medical therapy for their
symptoms. The strategies of medical therapy include inhibition of DHT production
within the prostate and blocking of alpha-1 adrenergic receptors in the urethra
and the neck of the bladder. Below are some examples of medications used
to treat BPH.
| Finasteride |
Competitive inhibitor of 5-alpha reductase, the enzyme that
converts testosterone to DHT in the prostate. |
| Tamsulosin |
Alpha-1 adrenergic receptor antagonist. Relaxes the smooth
muscle of the urethra and neck of the bladder. |
Patients with more severe disease are treated with more aggressive
therapies. These include:
| Transurethral resection of the prostate (TURP) |
This is the most effective treatment but is associated with
the most complications. |
| Microwave Treatment |
This is a new therapy in which microwave radiation is
focused on the hyperplastic areas of the prostate. This has also been
associated with certain complications. |
With surgery and pharmaceuticals carrying such a high monetary cost and the
risk of potentially debilitating side effects, there has been a desire to develop safer
and better therapeutic options. Such alternatives have been explored in Europe and Japan
where natural products to treat BPH have been pioneered.
The use of plants and herbs for medicinal purposes represents nearly 50% of
medications dispensed for BPH in Italy and is a first line therapy for mild to moderate
obstructive symptoms in Germany, representing >90% of drugs prescribed
for BPH.
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