Prostate enlargement (benign prostatic hyperplasia)

 | March 1, 2008

Prostate enlargement (benign prostatic hyperplasia)

When a man reaches about age 25, his prostate begins to grow. No one knows why, although doctors speculate that age-related changes in hormone levels play a role, as may dietary factors.

One popular theory suggests that the prostate begins to grow because of shifts in the balance between testosterone, a male hormone, and estrogen, a female hormone that is present in men in small amounts. Testosterone production declines with advancing age, changing the ratio of testosterone to estrogen. Some animal studies have shown that this shift in hormone balance may start a chain reaction, causing the cell proliferation seen with prostate enlargement. Other animal studies suggest that the accumulation of the male hormone dihydrotestosterone (DHT) in the prostate may encourage cells to divide.

Evidence suggesting a link between prostate enlargement and Western dietary patterns has also emerged. In 2002, researchers for the 52,000-participant Health Professionals Follow-up Study reported in The American Journal of Clinical Nutrition that men with a higher intake of calories, protein, and some specific forms of polyunsaturated fats were more likely to develop prostate enlargement than those who ate less. High levels of calcium in the diet may also play a role.

This natural enlargement that comes with age is called benign prostatic hyperplasia (BPH), or sometimes benign prostatic hypertrophy. It is the most common cause of prostate enlargement. Indeed, if a man lives long enough, he will almost certainly experience some degree of BPH. Keep in mind that this is a benign condition that doesn't lead to cancer (although the two problems can coexist).

Although 50% to 60% of men with BPH may never develop any symptoms, others find that BPH can make life miserable. As a result, many men seek treatment. The good news is that treatments are constantly being improved. More choices in medications are available, and surgical techniques are being refined to be more effective with fewer side effects than ever before.

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How BPH progresses

As the prostate enlarges, it starts to press against the urethra and the bladder, like a foot stepping on a garden hose or fingers pinching a soda straw. This gradually obstructs the flow of urine, forcing the bladder to work harder to push urine through the urethra. But straining to urinate, although unavoidable, only makes matters worse. Like any muscle, the bladder wall becomes thicker with exercise. This reduces the amount of urine the bladder can hold and causes it to contract even when it contains small amounts of urine, causing more frequent urination. Eventually, the bladder becomes so thick that it loses its elasticity and can no longer empty itself.

The narrowing of the urethra and partial emptying of the bladder cause many of the problems of BPH. You may feel as though you have to urinate immediately, yet have to strain to do so. You may have a weak urinary stream or one that stops and starts. You may dribble after urinating or feel as if you're not emptying your bladder completely. And you may feel the need to urinate frequently — even every few minutes — causing many awakenings during the night. Some men also experience urinary incontinence, the involuntary discharge of urine.

The course of BPH varies from one man to the next. In some, the disease may progress to a certain point and reach a plateau of mild symptoms that never worsen, or the prostate may continue to enlarge but grow away from the urethra, causing no additional impingement. Particularly in the early years of the condition, the symptoms may abate before worsening again. In other men, the disease progresses and the symptoms intensify steadily, year after year. In the worst cases, the prostate can grow as large as a grapefruit.

Most physicians advise against medical or surgical treatment for men with mild symptoms, because the side effects of the treatment outweigh the potential benefits. But if the symptoms worsen, ordinary activities may become a challenge. A 65-year-old man may find it hard to sit through a lengthy meeting without having to excuse himself to use the bathroom. He may need to request an aisle seat at the theater or a sports event, so he can rush to the bathroom at any time. If he has a problem with leakage, he may begin wearing dark clothing to conceal his incontinence. And he may feel fatigued during the day because of frequent nighttime awakenings.

BPH can also produce complications that, while not life-threatening, nonetheless require medical attention. If the blockage is so severe that it keeps your bladder from emptying completely, you may be vulnerable to frequent urinary tract infections. The risk of developing bladder stones also increases. The growth of the prostate can rupture blood vessels in the urethra, causing blood to appear in the urine. If obstructive BPH goes untreated for too long, the bladder may become distended, its muscular wall may weaken, and you may be unable to squeeze any urine past the obstructing prostate gland, a condition known as acute urinary retention. The bladder may become so distended that urine cannot adequately empty from the kidneys. In the most severe cases, this can lead to kidney failure. And not being able to urinate at all is a medical emergency, requiring the temporary passage of a catheter, a thin hollow tube, through the urethra to allow the bladder to drain. Fortunately, such complications are uncommon because most men seek medical attention well before serious problems develop.

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Getting help

It's important to see a doctor if you experience the symptoms of BPH. During an initial evaluation, the doctor will take a medical history. Expect questions about your urinary flow problems, how long the symptoms have been present, and any prior genitourinary surgery or procedures. Most likely, he or she will ask about your health habits and any medications that may have made the symptoms worse.

Your doctor may also ask you to complete a questionnaire, the American Urological Association Symptom Index, to help evaluate the severity of your BPH. Questions include these:

Over the past month, how often have you had a sensation of not having emptied your bladder completely after you finished urinating?

Over the past month, how often have you had to urinate again less than two hours after you finished urinating?

Over the past month, how often have you stopped and started again several times while urinating?

Over the past month, how often have you found it difficult to postpone urination?

Over the past month, how often have you had a weak urinary stream?

Over the past month, how often have you had to push or strain to begin urination?

Over the past month, how many times, typically, did you get up to urinate between the time you went to bed at night and the time you got up in the morning?

An adequate physical exam and diagnostic workup includes a DRE and, if you and your doctor concur, a PSA test. It also includes several other laboratory tests, including a urinalysis, which allows your doctor to rule out bacterial infections and look for untreated diabetes, which can produce frequent (and nocturnal) urination.

In a sense, your lifestyle will determine how burdensome you find BPH. The symptoms that disrupt the day-to-day activities of one man may have less effect on another who perhaps spends much of his day at home. Work with your physician to determine what, if any, treatment is the best choice.

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Treating BPH

When symptoms are not particularly bothersome, you and your doctor may choose to do nothing other than "active surveillance," which involves regular monitoring, but no treatment. For more troubling symptoms, most doctors begin by recommending a combination of lifestyle changes (see "Tips for relieving BPH symptoms") and medication. Often this will be enough to relieve the worst symptoms and allow you to avoid surgery.

Should surgery become necessary, keep in mind that there are several surgical techniques available and that just because a technique is new doesn't mean it is better. Before proceeding, check with your health insurance company to make sure your choice is covered. Not every health plan covers every procedure, and because there are several effective treatments, you may want to choose one that your insurance will cover. Also, if you choose a surgical procedure, find a surgeon who has extensive experience with that specific procedure.

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Medications

Your doctor is likely to recommend medication to treat BPH before suggesting surgery (see Table 3). The FDA has approved two types of drugs for BPH: a group of drugs known as alpha-reductase inhibitors, including finasteride (Proscar), and dutasteride (Avodart), and the alpha blockers, including terazosin (Hytrin), doxazosin (Cardura), tamsulosin (Flomax), and alfuzosin (Uroxatral). These two classes of medication work in different ways to help alleviate urinary symptoms and often work well together. In addition, some men may find further benefit with certain herbal remedies.

Simply put, alpha blockers deal with the "going" problem by relaxing certain muscles in the prostate and urinary tract. The alpha-reductase inhibitors deal with the "growing" problem by reducing the size of the prostate. The alpha-reductase inhibitors act slowly, taking two months or longer to have an effect. Indeed, you may not see the maximum benefit until you've been taking the medication for several years. These drugs work best for men with large prostates. (Your doctor can give you a rough estimate of the size of your prostate by doing a DRE.) Alpha blockers, at least in some men, reduce symptoms much more quickly. In general, alpha blockers are better at relieving urinary symptoms such as difficult or frequent urination. But the alpha-reductase inhibitors have a stronger track record for reducing the chance that you'll need surgery or will experience complications such as acute urinary retention that occur when the prostate gland is large. With this in mind, some doctors prescribe a combination of both kinds of drugs for men with large prostates.

You generally need to take these drugs indefinitely to maintain their benefits. If you stop taking the medication, the symptoms usually return to their previous levels. Over all, compared with surgical procedures, medication has a lower risk for serious adverse effects, leading most men to choose drug therapy as their initial treatment.

Alpha blockers. For men with moderate enlargement of the prostate and moderate urinary problems that are too bothersome for active surveillance, doctors often first prescribe an alpha blocker. Originally approved to treat high blood pressure, alpha blockers relieve urinary symptoms by relaxing the smooth muscle tissue in the prostate and the surrounding capsule. This relieves constriction of the urethra and allows urine to flow more easily.

Alpha blockers come in two forms, called selective and nonselective. Because nonselective alpha blockers can also lower blood pressure, they may not be the right choice for every man. For instance, some doctors are hesitant to prescribe nonselective alpha blockers for men who are already on another blood pressure medication. Taking several antihypertensive drugs at once can cause an excessive drop in blood pressure, producing faintness or dizziness, especially when getting up from a chair or out of bed. Sudden episodes of low blood pressure can be dangerous for men with vascular disease, which places them at high risk for a heart attack or stroke. However, the two selective alpha blockers, tamsulosin and alfuzosin, are more specific to the prostate and don't lower blood pressure, making them useful for men who don't need or couldn't tolerate this additional effect.

In addition, some men on alpha blockers experience dizziness, lack of energy, swelling of the ankles, or retrograde ejaculation (in which semen flows back into the bladder rather than out through the penis). You may need to make several visits to your doctor to arrive at the appropriate medication and the right dose.

Alpha-reductase inhibitors. These medications help shrink the prostate, but they work slowly and may be less effective at relieving symptoms than the alpha blockers. Finasteride and dutasteride shrink the prostate by changing its hormone balance. Specifically, they reduce levels of the male hormone dihydrotestosterone (DHT), which plays a role in prostate growth. The drugs interfere with the action of 5-alpha reductase, an enzyme that converts testosterone to DHT. Interestingly, their role in reducing DHT levels also makes these drugs useful in treating hair loss in men.

A 1996 analysis of six studies comparing finasteride against a placebo found that the medication works somewhat better in men with large prostates, and that it may not be a good choice for those with smaller glands. Further news came in a 1998 New England Journal of Medicine study, involving 3,040 men, which showed that for men with symptoms of urinary obstruction and prostatic enlargement, finasteride provided significant benefits. Patients who took it for four years experienced fewer symptoms, a reduction in prostate size, an increase in urinary flow rate, and less likelihood of surgery or acute urinary retention. A year later, researchers reported that finasteride was most effective in men with large prostates and with PSA levels of 1.4 nanograms per milliliter (ng/ml) or higher. In 2002, the Medical Therapy of Prostatic Symptoms (MTOPS) trial found that using finasteride in combination with the alpha blocker doxazosin helped slow progression of BPH by 67%, better than either drug alone.

These medications tend to reduce PSA levels by about 50%, which should be considered in early monitoring for prostate cancer. You and your doctor need to discuss this issue; most physicians advise obtaining a baseline PSA value before beginning finasteride treatment.

Be advised that finasteride and dutasteride can interfere with sexual function, although this is relatively uncommon. As the drug shrinks the prostate gland, a small number of sexually active men (3.7% in the original clinical trials) have difficulty achieving erections, and some (3.3%) experience a decline in sexual desire. A few (2.8%) notice a decrease in the volume of their ejaculate, which some may find bothersome.

Saw palmetto and other herbs. So far, evidence is conflicting for saw palmetto, an herbal remedy sometimes used as a nonprescription treatment for the urinary effects of BPH. Saw palmetto is made with extracts of the fruit of the saw palmetto plant, a dwarf palm that grows in the southeastern United States. The active ingredients are thought to be the various sterols (hormone-like substances) in the plant extract. American Indians have long used saw palmetto as a diuretic.

A 1998 article in The Journal of the American Medical Association studied saw palmetto's effectiveness. The authors reviewed 18 separate studies of various saw palmetto products and concluded that the supplements moderately improve urinary tract symptoms and urine flow, about as much as the prescription drug finasteride.

However, a 2006 study published in The New England Journal of Medicine found saw palmetto to be no better than placebo. In this double-blind, placebo-controlled study, researchers assigned 225 men with moderate to severe BPH symptoms to take either a placebo or 160 milligrams (mg) of saw palmetto extract twice a day. After one year, there was no significant difference between the two groups in BPH symptoms such as prostate size, PSA level, or maximal urinary flow.

Saw palmetto appears to have few side effects, and some clinical studies suggest that it doesn't cause erectile dysfunction, a rare but potential side effect of finasteride.

The drawback to this herbal supplement, as with most nonprescription herbal products, is that its composition and dosage have not been standardized and the FDA doesn't regulate it. If you decide to use saw palmetto, tell your doctor so he or she will be alert to possible interactions between it and any other medications you take. The dosage used in most of the studies was 320 mg per day.

Although a variety of other plant products are marketed as prostate remedies, so far there is too little evidence of their effectiveness and inadequate information to determine standard dosages. Some of these products are as follows:

Pygeum africanum. An extract of an African evergreen tree, pygeum is sometimes used as a treatment for urinary symptoms. The Cochrane Database of Systematic Reviews reports that this substance moderately but significantly improves urologic symptoms and flow. And one study, involving 263 men recruited at eight sites in Europe, found that participants who took pygeum experienced improvements in urinary symptoms. However, pygeum does not appear to reduce the size of the prostate gland or reverse the process of BPH.

Beta sitosterols. Preparations containing beta sitosterols — derived from the South African star grass, Hypooxis rooperi, and also from species of Pinus and Picea — are sometimes used to treat symptoms of BPH. A review published in the Cochrane Database of Systematic Reviews says the evidence suggests that these substances improve urinary symptoms and urinary flow, but their long-term effectiveness, safety, and ability to prevent BPH complications are not known.

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Transurethral resection of the prostate

If the results of active surveillance and medication are not satisfactory, you and your doctor will need to determine whether surgery or another procedure may be right for you. In the past, if BPH symptoms were severe — or if they were modest but still disrupted a patient's life — doctors almost universally recommended a surgical removal of prostate tissue called transurethral resection of the prostate (TURP). Although TURP is still widely used and is considered the "gold standard" by many doctors, alternatives are available.

TURP, often inelegantly referred to as the "Roto-Rooter" technique, is an incision-free surgical procedure that reduces prostate tissue with an electrical loop. TURP remains the most common form of prostate surgery, and is usually more successful than medication. It relieves urinary obstruction in at least 75% of cases, and the improvement is usually long-lasting. However, urinary problems can recur if the prostate tissue grows back. Not surprisingly, the younger you are, the more likely it is that you'll eventually need another treatment.

The 60-minute procedure takes place in an operating room under general or spinal anesthesia, given just before the operation begins. Men usually have an enema the preceding night and are forbidden to eat or drink for eight hours before the anesthesia. During the procedure, the surgeon uses an instrument called a resectoscope to view the prostate (see Figure 4). The surgeon threads the resectoscope through the penis to the prostate, then uses the electrical loop to cut away the overgrown tissue that's pressing against the urethra. Men generally spend one to two days recovering in the hospital.

While recovering, the patient urinates through a thin tube (catheter) inserted through the penis into the bladder and left in place for a day or two to empty the bladder. Once home, he may have to restrict heavy physical activity for two weeks or more to prevent bleeding.

Most men who've had a TURP experience retrograde ejaculation during sexual activity. This occurs because the surgery destroys the valve that would ordinarily prevent this from happening. The semen, which flows backward into the bladder, is later flushed out with the urine. While not harmful to a man's health, retrograde ejaculation does make it more difficult to father children, a factor that patients must weigh when considering TURP, although many men having this procedure have already completed their families.

The more worrisome complications of TURP occur in about 5% to 10% of patients. These include blood loss, impotence, urinary incontinence, infections, and complications related to the anesthesia. Although relatively uncommon, these side effects do happen, and they need to be considered when choosing treatment options. Interestingly, a study of U.S. veterans has suggested that TURP is no more likely to cause sexual problems or incontinence than watchful waiting.

On rare occasions, the prostate has grown so large that TURP isn't a good option. Instead, open prostatectomy is necessary. In this procedure, the surgeon removes the obstructing tissue through an incision in the lower abdomen, leaving the rest of the prostate gland in place. Generally, this operation requires a longer hospital stay. On the other hand, compared with TURP, it reduces the likelihood that the tissues will grow back or that problems will recur.

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Laser surgery

Laser surgery is widely available for treating BPH. Although usually performed in a hospital setting, laser surgery is less traumatic than TURP, and most patients go home the same day.

To perform a laser procedure, the surgeon begins by guiding a fiber through the urethra to the prostate. This fiber conducts the laser light to the target area. Then the surgeon uses the laser to burn away tissue that obstructs the urine flow. Dead tissue that's not immediately vaporized is later expelled in the urine. This technique removes prostate tissue with less bleeding than standard TURP.

Surgeons originally used low-energy lasers for these procedures. Now high-energy lasers are becoming more popular. The advantage of these over TURP or low-energy laser sources to remove prostate tissue is that bleeding is reduced and the catheter may be removed much earlier, often within 24 hours. Overnight hospitalization often is not needed. One type of high-energy laser, called a green light or KTP laser, enables the surgeon to view the prostate while performing the procedure, and also to remove large amounts of tissue with little bleeding. Indeed, patients on blood-thinning medication may have green light laser prostatectomy while still taking these medications.

Research suggests that patients who have laser procedures are just as likely to experience urinary incontinence and retrograde ejaculation as are those who undergo TURP. If you have a low-energy laser procedure, you may need to use a catheter for urination for a longer time than you would after TURP.

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Other treatments for BPH

A variety of other treatments for BPH are in use. Some are not available everywhere, and some aren't covered by health insurance. However, they can be viable options for certain men with BPH.

Transurethral microwave thermotherapy (TUMT). TUMT is one of a group of techniques known as "heat therapies," which use heat to destroy prostate tissue, achieving results similar to TURP. In TUMT, the doctor guides a thin catheter carrying a miniature microwave generator through the penis to the prostate. There, microwaves destroy some of the prostate tissue and relieve pressure on the urethra (see Figure 5). A cooling jacket around the generator protects the urethra. The procedure takes about an hour and can be performed on an outpatient basis.

The FDA approved the Prostatron, the first TUMT device sanctioned for use in the United States, in 1996. Although the FDA found the device safe and effective for urinary symptoms such as urgency, frequency, and intermittent flow, the treatment did not correct incomplete emptying of the bladder or a weak urinary stream. Several other TUMT devices are now being used in the United States.

TUMT appears to be less effective than TURP, according to a 2001 study in The Journal of Urology . This study reported that 20% of men who underwent TUMT needed additional treatment after three years, compared with 13% of those who received TURP. A larger review of studies produced an even greater difference, with researchers concluding that only 5% of men who underwent TURP required additional treatment.

Transurethral needle ablation (TUNA). TUNA is a thermal approach that uses low-level radio waves delivered through twin needles to heat and kill obstructing prostate cells. Shields protect the urethra from damage. Long-term effectiveness is unknown, but one study demonstrated that TUNA is more effective than medication but less effective than TURP.

Transurethral incision of the prostate (TUIP). TUIP also involves inserting an instrument into the prostate via the penis. But rather than cutting away excess tissue, the surgeon makes one or more deep lengthwise incisions in the prostate tissue at the site of the urethral constriction. This opens the urethral passage, relieving pressure on the urethra and improving urine flow. Spinal or general anesthesia is generally used for TUIP, which can be performed on an outpatient basis or during a one-day hospital stay. Recovery usually takes five to seven days.

TUIP is not an option for every patient. Men whose prostates are only modestly enlarged are the usual candidates for this procedure. The benefits appear to last. Over a five-year period, the chance of needing further surgery is 8% to 10%, somewhat higher than the comparable figure for TURP (5%). There appear to be fewer postoperative complications — including retrograde ejaculation, urinary incontinence, and blood loss — than with TURP. While a quarter of men who've undergone TUIP experience retrograde ejaculation, that figure exceeds 70% for those who've had TURP. As a result, TUIP patients remain fertile after the procedure. Consequently, it's often chosen by men with only moderately enlarged prostates who may still want to father children.

Prostatic urethral stents. This procedure uses a small, springlike mesh cylinder called a prostatic urethral stent, which is typically made of titanium. The doctor inserts the stent through the penis and, after positioning it in the narrowed area of the urethra, releases it to widen the channel, relieving pressure from the prostatic tissue and allowing for easier urination. This quick procedure requires only local or spinal anesthesia, involves no loss of blood, and is often done in an outpatient surgical center.

However, prostatic urethral stents are of limited use, most often in elderly men who have severe prostate enlargement, but whose overall health is so poor that surgery would be risky. In many cases, urinary obstruction gradually returns because of a process called hyperplastic epithelial reaction, in which prostate tissue protrudes through the mesh and causes renewed blockage. Nevertheless, there's rarely a complete reblockage of urinary flow, although additional surgery may be required in some cases.

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Review Date: 2008-03-01

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