What is Benign Prostatic Hyperplasia (BPH)?

Benign prostatic hyperplasia (BPH) stands for a noncancerous (benign) enlargement (hyperplasia) of the prostate gland.

The prostate gland is located beneath the urinary bladder and surrounds the urethra through which the urine passes. At birth, the gland is about the size of a pea. It grows slowly during childhood, rapidly at puberty, and normally reaches full development (about the size of a walnut) by age 25. Growth after that is “unwanted”.

Unfortunately, most men in their mid- to late 40s will experience “unwanted” growth of the prostate. The exact causes of the growth are not clear. The relative levels of the male hormone, testosterone, and female hormone, estrogen, as well the changes of the gland’s sensitivity to these hormones may play a role.

Depending on the degree of the enlargement, about 50 percent of men with BPH can have some obstruction at the outlet of their bladder and experience some of the following signs and symptoms:

• Weak urine stream
• Difficulty starting urination
• Stopping and starting while urinating
• Dribbling at the end of urination
• Straining while urinating
• Frequent need to urinate
• Increased frequency of urination at night (nocturia)
• Urgent need to urinate
• Not being able to completely empty the bladder
• Blood in the urine (hematuria)
• Urinary tract infection

In the United States, approximately 20 million men over the age of 50 years suffer from BPH, resulting in an estimated 6.4 million office visits and 400,000 hospital admissions annually.

BPH Diagnosis and Treatment

An evaluation for enlarged prostate will likely include:

• Detailed questions about your symptoms and medical history.
• Digital rectal exam (DRE): to check if the enlargement may be due to cancer.
• Urine test: to help rule out infections or other medical conditions that cause BPH-like symptoms.

Other tests that help to confirm a BPH diagnosis include:

• Uroflowmetry. This test measures the volume and rate of your urine flow.
• Postvoid residual volume (PVR) test. Measures the volume of urine left in the bladder after voiding (often done using ultrasound imaging).
• Urodynamic pressure-flow studies. This test uses a urethral catheter to measure bladder pressure and function and the flow rate during voiding. It often needs a second catheter in the rectum. The procedure takes 30 to 60 minutes.
• Transrectal ultrasound (TRUS). This test measures the size of the prostate gland and provides information that helps in diagnosing prostate cancer. It uses a rectal ultrasound probe.
• Cystoscopy. A lighted lens (cystoscope) is inserted through the urethra into the bladder to visualize interior of the urethra and bladder.
• Intravenous pyelogram or CT urogram. A dye (mostly iodine-containing) is injected into a vein, and an X-ray or CT scan is taken of the kidneys, bladder and ureters. The dye helps outline the drainage systems of the kidneys.

Sometimes a prostate-specific antigen (PSA) test is used for symptomatic patients. The PSA test measures the blood level of PSA, a protein produced by the prostate gland and released into the bloodstream. When the prostate grows in size (such as BPH), or when prostate cancer grows, more PSA is produced and released into the bloodstream. The test is used for prostate cancer screening.

Treatment options for BPH fall into the categories of watchful waiting, medications, surgical procedures, and minimally invasive treatments.

• Watchful waiting.It’s a “wait and see” approach for most patients with mild to moderate symptoms.
• Medications:
• Alpha blockers: drugs that relax the smooth muscles of the bladder neck to improve the urinary flow rate.
• 5-alpha reductase inhibitors: drugs that inhibit the activity of the enzyme (5-alpha reductase) that mediate the growth of the prostate gland.
• Combination drug therapy: alpha blockers and 5-alpha reductase inhibitors are taken at the same time to achieve better results.
• Surgical treatments for BPH include:
• Transurethral resection of the prostate (TURP). A narrow instrument (resectoscope) is inserted into the urethra and small cutting tools are used to chip away excess prostate tissue surrounding the urethra. The cut pieces of prostate tissue are first carried to the bladder by flushing saline and then taken out of the bladder in the end through a bladder catheter. It is the most common surgery for BPH patients and relieves symptoms within a few days.
• Transurethral incision of the prostate (TUIP). This surgery is usually indicated for a small to moderately enlarged prostate gland.  Like TURP, TUIP also uses instruments that are inserted into the urethra.  But instead of removing prostate tissue, TUIP makes one or two small cuts in the prostate gland to enlarge the opening of the urethra.
• Laser prostatectomy surgery. A high-energy laser is used to destroy overgrown prostate tissue. The most common types of laser surgery are photosensitive vaporization of the prostate (PVP) and holmium laser enucleation of the prostate (HoLEP). This uses a high-energy, low-penetration laser that destroys prostate tissue on contact. Compared with TURP, laser surgery causes significantly less blood loss and recovery is quicker. Laser surgery to relieve BPH symptoms is relatively new, so its long-term effectiveness needs to be established.
• Open prostatectomy. It is generally performed only if the patient has an excessively large prostate, bladder damage or other complicating factors.
• Minimally invasive treatments:
  • Transurethral microwave therapy (TUMT) This procedure uses microwave energy to destroy the inner portion of the enlarged prostate gland. A catheter is inserted into the urethra and a tiny internal microwave antenna inside the catheter delivers a dose of microwave energy that heats and destroys enlarged prostate cells. The procedure can be done in outpatient clinics and patients can go home on the same day.
  • Transurethral needle ablation (TUNA). This procedure uses radiofrequency energy. A cystoscope is inserted in the urethra and needles are placed into the prostate gland under visual guidance. Radio wave (energy) is delivered through the needles to heat the overgrown prostate tissue. It is often performed as an outpatient procedure.
  • Laser therapy. A small tube containing a laser fiber is inserted through a cystoscope into the urethra and punctured into the prostate gland. Laser energy is delivered through the laser fiber to heat and destroy the tissue and shrink the gland.
  • High energy focused ultrasound (HIFU). An ultrasound probe is placed in the rectum behind the prostate gland and ultrasound energy is directed toward the prostate gland to destroy and shrink the prostate gland.
  • Prostatic stents. A stent is a tiny metal coil that is inserted into the urethra to open up the lumen and keep it open. Tissue grows over the stent to hold it in place.

NIRS Application in BPH Treatment

Over the last decade there has been a dramatic increase in minimally invasive surgical therapies like transurethral microwave thermotherapy or TUMT [1]. Data from the Centers for Medicare and Medicaid Services (CMS) indicate 38% annual growth in the number of TUMT procedures performed on Medicare patients in the United States over the past five years and in 2005 TUMT was ranked among the top 110 procedures in allowed charges [2].

Previous studies using Doppler ultrasound observed that thermal therapy for BPH causes an additional increase in regional blood flow at the beginning of treatment, which is followed by a decrease or cessation of blood flow as sufficient thermal energy accumulates to cause blood and tissue coagulation.

Urodynamix is developing an instrument (NIRS TUMT) that applies near infrared spectroscopy (NIRS) technology to monitor the hemodynamic status of the prostate gland in real-time during a TUMT procedure. The NIRS instrument monitors the prostate tissue blood supply and hemodynamic status to help the physician deliver the optimal treatment dose (energy level and amount) to the prostate.

A study published at the 2009 AUA Annual Meeting by scientists from Capital Medical University (China), Boston Scientific (USA) and Urodynamix indicates that for an in vivo canine prostate model, the NIRS device detected an initial rise in oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) concentrations, reflecting the thermal-induced vasodilatation. The initial rise in HbO2 and/or Hb was followed by a precipitous drop as thermal coagulation progressed reflecting a rapid reduction of blood volume/flow due to thermally induced vascular occlusion and/or thermal degradation of the hemoglobin and tissue proteins in the monitored volume.

The study concluded that NIRS monitoring of the prostate for changes in blood volume/flow may provide the ability to non-invasively monitor the progress of tissue coagulation during thermal therapies for BPH patients. It may allow physicians to optimize treatment for each patient despite individual variations in prostate blood flow and tissue volumes.

Click here to view the AUA 2009 poster.

References:

[1] Harkaway RC and Issa MM. Medical and minimally invasive therapies for the treatment of benign prostatic hyperplasia. Prostate Cancer and Prostatic Diseases 2006; 9: 204-214

[2] Centers for Medicare and Medicaid Services (CMS) utilization data - Part B claims data