Benign Prostatic Hyperplasia – Prostate Cancer – Prostatitis

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Treatments for Benign Prostatic Hyperplasia. Part 2

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α-Adrenergic blockers

It has been suggested that the dynamic component of obstruction, smooth muscle tone in bladder heck, prostate, urethra, and prostatic capsule, is responsible for the variation in symptoms. Prostatic smooth muscle tone is regulated by the autonomic nervous system. The contractile response of prostatic tissue to norepinephrine and its abolishment by pretreatment with OC-adrenergic antagonists was first demonstrated by Gaine and colleagues during the 1970s. α1 and α2-receptors have recently been identified in human prostate and bladder neck by radioligand receptor studies. Contractile response is predominantly mediated by α1-receptors.

Well-controlled studies have been performed demonstrating the efficacy of phe-noxybenzamine (non-selective α-adrenergic antagonist), prazosin (α1-adrenergic antagonist), and terazosin (α1-adrenergic antagonist) in the treatment of Benign Prostatic Hyperplasia. Meaningful improvements in symptom score, global assessment, and urodynamic parameters (peak flow rate, mean flow rate) have been documented with these agents. Side effects have been minimal, and hypotension was not a problem.

α -Adrenergic blockade can be expected to provide a degree of relief from outlet obstruction. Once long-term experience with these agents has been gained, their role in the management of Benign Prostatic Hyperplasia can be clarified.

Anticholinergic agents

A literature review of the medical management of Benign Prostatic Hyperplasia is remarkable for the fact that the anticholinergic agents are virtually ignored. Approximately 75% of patients with BPH have significant irritative symptoms, such as frequency, urgency, and nocturia, which are considered to be due to detrusor hypertrophy. In many of these patients, the obstructive symptoms (Table 3) are minor and of little concern. The efficacy of such medications as oxybutynin (Ditropan) in the treatment of unstable bladders is clear. It could be that these medications are not used more often for fear of causing urinary retention.

Table 3. Obstructive Voiding Symptoms

• Hesitancy

• Intermittency

• Terminal dribbling

• Impairment of size and force of urinary stream

• Sensation of incomplete emptying

Of the 75% of patients with irritative symptoms, 33% will have persistent symptoms after relief of outlet obstruction. It is useful to know whether these symptoms can be medically controlled. If they cannot, then the patient may have little benefit, symptomatically, from a transurethral prostatic resection (TUPR) and should be aware of this before the operation.

There are many causes for irritative voiding symptoms. The physician should rule out infection. If gross or microscopic hematuria is present, then bladder cancer must be ruled out. If the patient is adequately emptying his bladder, as determined by palpation, ultrasound, or postvoid catheterization, then a trial of anticholinergic medication, such as oxybutynin, 2.5 mg by mouth, is worthwhile. A significant number of patients benefit substantially; moreover the drug can occasionally be tapered and discontinued after 3 to 6 months without a return of symptoms. If outlet obstruction worsens, then one can proceed to prostatectomy, secure in the knowledge that any persisting irritative symptoms can be controlled after surgery.

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Treatments for Benign Prostatic Hyperplasia. Part 1

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Benign Prostatic Hyperplasia (BPH) is the most common neoplasm affecting humans. More than 400 000 prostatectomies are performed annually in the United States, second only to cataract extractions in charges to Medicare.

In an era of limited health care funds, the indications for and efficacy of traditional therapy must be reviewed. A variety of new therapies for BPH are being clinically evaluated. Any new treatment will need to show comparable efficacy, safety, and cost efficiency.

Natural history

Histologically detectable Benign Prostatic Hyperplasia has an increasing incidence with age, with virtually all men demonstrating hyperplasia by age 80. However, clinical enlargement is detected in only 50%. Of these, roughly half will develop symptoms sufficient to seek treatment. It is estimated that a 50-year-old man has a 10% to 20% chance of receiving surgery for relief of bladder outlet obstruction in his lifetime.

The symptoms of bladder outlet obstruction vary significantly over time. It has been proposed that oudet obstruction has both a static and dynamic component. Mechanical occlusion of the urethral lumen by the enlarging gland is the static component, while smooth muscle tone within the urethra, prostate, prostatic capsule, and bladder neck is the dynamic element.

The clinical course in patients with moderate symptoms is unpredictable. Several investigators have looked at long-term follow up in these patients. Ball and colleagues followed 107 patients for a minimum of 3 years. Ten required surgery, leaving 97 for evaluation by subjective and objective criteria. Subjectively, 24% were worse, 29% were better, and 47% reported no change. Objectively, urodynamic parameters were assessed: 49% deteriorated, 28% improved, and 23% remained stable.

There was significant overlap between the groups, indicating a poor correlation between subjective and objective criteria. Other studies support this lack of agreement between symptomatic outcome and urodynamic parameters in Benign Prostatic Hyperplasia.

The accepted objective indications for prostatectomy include acute retention azo-temia secondary to outlet obstruction and recurrent urinary tract infection related to chronic residual urine. However, fewer than 20% of prostatectomies are carried out on the basis of objective criteria; the rest are performed for symptomatic improvement. Therefore, the assessment of symptoms and subjective response to therapy is essential in treatment decisions and evaluation of therapeutic intervention.

Hormonal therapy

The prostate is an aggregation of tubuloalveolar glands, supported by an unusually dense fibromuscular stroma. The stroma is made up of fibroblasts, smooth muscle cells, and collagen. Benign prostatic hyperplasia is the result of proliferation of glandular epithelium and fibromuscular stroma. In a morphologic study, Bartsch and colleagues determined that Benign Prostatic Hyperplasia results primarily from an increase in stroma, as the normal stroma to epithelium ratio increases from 2:1 to 5:1.

The development of BPH requires aging and the presence of androgens. Elimination of androgens, either medically or surgically, will result in decreased protein synthesis, in tissue involution, and in cell death in the prostate. Huggins and Stevens demonstrated involution of the prostatic epithelium with little effect on the stroma in men with BPH after castration. Similarly, Peters and Walsh reported a reduction of 40% in epithelial volume and 20% in stroma in nine patients treated with the luteinizing hormone-releasing hormone agonist nafarelin acetate. As BPH appears to be primarily a disease of the stroma, one would expect androgen ablation to have a limited role.

Nevertheless, a variety of agents inducing androgen withdrawal have been studied (Table 1). There are valid methodologic concerns with these studies; however, several trends are evident. All have been shown to reduce size by 30% to 40% over 3 to 6 months. This reduction is reversible within 6 months of stopping the agent. The stromal portion is responsible for incompleteness of shrinkage, as biopsies reveal the response is primarily epithelial. Unfortunately, no trial assessed subjective outcome using a standardized symptom score, and most did not use placebo controls. The mean improvement in peak urinary flow rate was approximately 33%. These urodynamic changes were clinically significant.

Table 1. Drugs Used for Androgen Deprivation
• Cyproterone acetate
• Buserelin acetate
Leuprolide acetate
• Nafarelin acetate
• Flutamide

These agents clearly reduce gland size, but they do not create a functionally unobstructed state. They are also limited by side effects of impotence and hot flushes. As their effect is reversible, continuous therapy is needed. Given present life expectancies, this represents an enormous potential cost (Table 2).

Table 2. Relative Cost of Treatment Options

Treatment

Dose

Diethylsfilbestrol 1 mg TID
Cyproterone acetate

and

Diethylsfilbestrol

50 mg BID

0.1 mg daily

Leuprolide acetate

and

Flutamide

7.5 mg lM every 4 wks

250 mg TID

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Moderate symptoms of benign prostatic hyperplasia. Part 2

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Questions and Answers

1. Have similar studies been done comparing drug treatment to surgery or watchful waiting?

No. It’s very unlikely that anyone could get funding for such a study. It’s pretty clear that surgery is much more effective than medication.

2. Can watchful waiting really be considered a treatment that can succeed or fail?

Yes, there’s a huge amount of improvement that occurs in watchful waiting over time, particularly if they do the behavioural approaches you described – avoid medications that make it worse, stay away from caffeine and alcohol, don’t drink fluids in the evening and empty the bladder before going to bed. These things seem to have a significant effect on a lot of men. Also, benign prostatic hyperplasia symptoms come and go naturally – you see that even with placebo, things just get better. If you’re not really badly bothered, watchful waiting and drugs are reasonable alternatives, but if you’re badly bothered, you’re probably wasting your time with these options.

3. Does the age of the patient make watchful waiting more or less appropriate?

Ironically, it’s in the younger patients that more thought should be given about drug treatment, because they have so much more time to pile up the costs and side effects. If you’re young and choose medication, you have to understand that you’re potentially going to be on them for the rest of your life. The price of the drugs will surpass that of surgery after a few years, and you still don’t know if you’ll eventually need surgery anyway. I always recommend that, if a young man is going to start on the drugs, he do so for two or three months, then stop for a couple of months and see if it makes any difference, because so many men will get better anyhow – it may be no better than a sugar pill. They should stop and start a few times before deciding to commit themselves to lifelong drug therapy, to make sure it’s working. For an older man with a more limited life expectancy, he has less time to benefit from surgery and more risk for complications. Therefore, drugs may actually make more sense in an older man. This is the opposite of what’s going on in most practices.

4. Can you explain the discrepancy between the men’s evaluation of sexual performance and that of their partners?

The real point is that neither surgery nor watchful waiting differed in their effect on potency. If you looked at those men who were actually impotent, their spouses were more likely to agree. But it’s not unusual for the man and the wife to have different perceptions of sexual function. The disagreement wasn’t significant.

Editorial Commentary

This is the only study that’s ever looked at TURP, which is a very common surgery, and compared it to watchful waiting. We looked at people for at least three years and up to six years. The study shows that, particularly for men who are bothered, surgery is likely to be very beneficial and not likely to result in impotence or incontinence. Prior to this, all the studies showing that surgery results in impotence were not controlled. Many older men become impotent anyway, and then blame the surgery – you always want to look back and blame something. In this study, we looked at that very carefully and found no evidence that it’s true.

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Moderate symptoms of benign prostatic hyperplasia. Part 1

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The urinary symptoms of benign prostatic hyperplasia (BPH) can range from very mild to severe enough to require prompt surgical treatment. Men with moderate symptoms of BPH do not face immediate health risks, but are typically bothered by symptoms such as frequent urination, dribbling and a hesitant urinary stream. These men are presented with the options of drug therapy, surgery to reduce the volume of the prostate, or watchful waiting, which monitors symptoms and employs behavioural measures, like learning to relax the muscles while urinating and eliminating caffeine and alcohol, to avoid or delay surgery. This study set out to compare the effectiveness of surgery and watchful waiting in managing moderate symptoms of BPH.

Between 1986 and 1989, 556 men age 55 or older were recruited into the study at participating U.S. veterans’ medical centres. All had moderate urinary symptoms of benign prostatic hyperplasia, making them appropriate candidates for either watchful waiting or surgery. After obtaining the consent of participants and conducting baseline exams, the researchers randomly assigned patients to either surgery, consisting of transurethral resection of the prostate (TURP), or watchful waiting, with consideration given to the severity of symptoms and the hospital in which care would be administered. Those assigned to surgery underwent the operation within two weeks. The men were seen by a general practitioner six to eight weeks after the beginning of the study, and then twice a year for three years.

The effectiveness of treatment was judged in two ways. The first was according to the number of treatment failures in each group. Failure was defined as any of the following: death, persistent urinary retention, residual urine (the amount left in the bladder after urinating) of over 350 ml, incontinence requiring the use of pads or other devices, a doubling of the serum creatinine level (a measure of kidney function) over the course of the study, or symptom scores over 23 at one visit or over 20 at two visits in a row.

Treatments were also judged according to changes in the urinary symptoms men experienced and in how much these bothered them. Peak urinary flow and residual urine were measured at each follow-up visit. Questionnaires were completed at the start, at one year and at the end of the study to provide a score representing how much benign prostatic hyperplasia symptoms interfered with daily life, sexual function and overall well-being.

Complications from prostate surgery were rare, and 78% of men were out of hospital four days after surgery. Ten percent of men who had surgery were diagnosed with prostate cancer after tests were done on the tissue that had been removed. Mortality rates over the three years were similar in the surgery and watchful waiting groups. As well, perceived changes in sexual performance were similar for the two groups, with 19% of the surgery group and 21% of the watchful waiting group reporting a worsening of sexual performance over the three years, with 3% in each group reporting an improvement. However, most of the spouses thought that the men’s sexual performance had been unaffected by either treatment.

Incontinence symptoms, defined as dripping urine or wetting their pants, were improved much more by surgery than by watchful waiting. At the start of the study, 22% of surgery patients and 18% of watchful waiting patients had reported moderate to severe incontinence. After three years, only 5.7% of the surgery group, but 12% of the others, were still bothered by this problem. In other words, among the men who had initially complained of them, these symptoms were reduced or eliminated in one-third of watchful waiting patients, but in about three-quarters of the surgery patients.

Treatment failures were more than twice as frequent in the watchful waiting group as in the surgery group (6.1 per 100 person-years as opposed to 3.0). Three problems accounted for most of the failures in the watchful waiting group: persistent urinary retention, high residual urine volumes and high symptom scores. Twenty men initially assigned to the watchful waiting group had surgery within the three years because of treatment failure.

This study found surgery to be more effective than watchful waiting for men with moderate benign prostatic hyperplasia symptoms. Men who reported being substantially bothered by urinary symptoms at the start appeared to benefit most from surgery. Ninety-one percent of the men who received surgery saw improvement in their symptoms, as opposed to 62% of those on watchful waiting. Men with very bothersome symptoms were likely to switch from watchful waiting to surgery within the three-year follow-up period. The authors conclude that, while men who are only mildly bothered by urinary symptoms of BPH may safely choose watchful waiting, men whose symptoms substantially reduce quality of life have the most to gain from TURP. A good number of those who choose watchful waiting are really only delaying surgery, rather than averting the need for it altogether.

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Don’t Forget Your PSA Test

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If you’re a young man, you’re probably not overly concerned about prostate cancer. If you are approaching the age of 50, you may be starting to wonder about it. If you’re over 50, chances are that you have already been screened for this disease by your doctor. In fact, testing for prostate cancer has been the focus of a significant amount of research in recent years. One test in particular, the measurement of a man’s PSA (prostate specific antigen), is revolutionizing the screening and treatment of this cancer.

The prostate is a walnut-sized, male sex gland located below the bladder and directly in front of the rectum. During intercourse, it produces a thick fluid that helps force sperm through the urethra and out of the penis. The prostate also produces PSA, an enzyme that liquefies seminal fluid permitting sperm to swim more freely. In the case of a healthy prostate, some of this prostate specific antigen leaks out into the bloodstream where it is either bound to blood proteins, or it is left “free” and unbound. According to recent research at the National Institute of Aging (NIA) and Johns Hopkins University School of Medicine, in cases of prostatic disease, including infection, prostate enlargement or cancer, increased levels of total PSA are readily detected in the blood. Elevated PSA readings would indicate the need for further diagnostic tests.

NIA and John’s Hopkins studies have shown that the rate of increase of total prostate specific antigen levels over time is one of the best predictors of prostate cancer. The ratio of free to total PSA can also predict whether prostate cancer is developing as well as its aggressiveness (i.e., whether it’s fast or slow growing). So when the time comes, remember your prostate specific antigen test – in the long run, your prostate might thank you.

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Casodex and Zolvadex improve advanced prostate cancer

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Casodex (bicalutamide / Zeneca) is a safe and effective treatment for advanced prostate cancer when used in combination with LHRH-A therapy (medical castration), a regimen known as CAB. Now two studies show that Casodex is effective when used as monotherapy. In one study, 288 patients with metastatic disease were randomized to treatment with Casodex alone or the CAB regimen. Of those treated only with Casodex, 70% had a favorable subjective response compared to 58% of patients on the CAB regimen. In the second study, treatment with Casodex led to a better quality of life.

A report on the use of Zolvadex (goserelin acetate implant / Zeneca) demonstrated that the drug improved five-year overall survival in those patients with locally advanced prostate cancer. The drug was given as adjuvant therapy, initiated simultaneously with radiotherapy and continued every four weeks for three years.

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Benign Prostatic Hyperplasia (BPH)

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The prostate gland is part of the male reproductive system. It is located just below the bladder and surrounds the urethra, the small tube through which urine travels out of the body. As men age, the prostate gland becomes larger. As it enlarges, it may press on the urethra and block the flow of urine out of the bladder. This condition is known as BPH, or benign prostatic hyperplasia. In men with Benign Prostatic Hyperplasia, the partial blockage of the urethra leads to irritation in the bladder, which eventually does not completely empty during voiding. The blockage and partial emptying of the bladder lead to a variety of problems, including a weak, interrupted or hesitant stream of urine, frequent urination (especially at night), a feeling of urgency to urinate, and leaking or dribbling of urine. For some men, these symptoms are simply annoying. Symptoms of prostate enlargement can also signal a more serious condition, such as prostate cancer. If BPH is not treated, it can cause serious problems over time, including urinary tract infections, incontinence (leaking urine), stone formation, and even permanent damage to the bladder or kidneys. It is very important to treat Benign Prostatic Hyperplasia in its early stages to avoid these complications.

Drugs Can Reduce Symptoms

The prostate gland enlarges as a normal process of aging in men, and usually does not cause urinary problems before age 40. This enlargement is considered “benign” because it is not cancerous. More than half of men in their 60s and even more in their 70s and 80s have an enlarged prostate. The cause of this enlargement is not completely understood. It is probably related to hormone levels, or the amount of dihydrotestosterone (DHT) in the prostate. DHT is a derivative of testosterone that may contribute to the growth of prostate gland cells. The urinary problems of BPH result from the narrowed urethra and the slow loss of bladder function, which leaves urine in the bladder even after urinating. The severity of the symptoms is not always related to the size of the prostate, since men with very large prostate glands may have almost no symptoms and those with less-enlarged prostate glands can suffer severe symptoms. Most men begin to feel urinary symptoms when the prostate gland enlarges enough to restrict urine flow. Problems can include a weak or interrupted flow of urine, difficulty in beginning the urinary stream, frequent urination, a feeling of urgency to urinate, or leaking urine. These symptoms can be made worse by some prescription drugs, such as anti-Parkinson agents, that cause urinary retention. Some antihistamine drugs can also worsen Benign Prostatic Hyperplasia symptoms.


How BPH Is Diagnosed:
Benign Prostatic Hyperplasia is typically diagnosed from either a patient’s history of urinary symptoms or after a routine physical. A digital rectal exam can give the doctor an idea of the size and shape of the prostate gland. Often a prostate-specific antigen blood test (PSA) is ordered to determine if this protein is elevated. A high PSA level is often found in men with prostate cancer. Other tests such as a rectal ultrasound of the prostate, and urinary tract studies such as a urinalysis, voiding cystourethrogram, post-void residual urine measurement, pyelogram x-ray or examination by cystoscopy can help determine the size of the prostate and whether urinary blockage is present. Although treatment of mild prostatic enlargement may not be necessary since many symptoms of BPH disappear on their own, many men with symptoms of Benign Prostatic Hyperplasia will eventually need either drug or surgical treatment for this condition.

Drug Therapy: Currently, four drugs relieve symptoms of Benign Prostatic Hyperplasia: finasteride, terazosin, doxazosin, and tamsulosin. Finasteride decreases the production of DHT, the hormone involved in prostatic enlargement. Finasteride not only stops the prostate from enlarging, but can actually shrink the prostate in some men, an effect seen after about 3 months of treatment. Unfortunately, finasteride works in less than half of patients. Terazosin, doxazosin, and tamsulosin belong to a class of drugs known as alpha-blockers. These drugs all relax the smooth muscle of the prostate and bladder to help improve urine flow out of the bladder. Alpha-blockers reduce the urinary symptoms of Benign Prostatic Hyperplasia but do not decrease the size of the prostate. These drugs also lower blood pressure, a side effect, and they can be used to treat men with high blood pressure as well as BPH. Other side effects of alpha-blockers are headache, dizziness, and weakness. These can sometimes be avoided by starting with a low dose and slowly increasing it over several weeks. Alpha-blockers are effective in about 70% of patients. Persons who have symptoms of Benign Prostatic Hyperplasia should not ignore these symptoms, but see their doctor for a complete examination.

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The Prostate. Part 5

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Prostate Cancer: Medical or Surgical Castration?

Some 30 to 40% of men over 50 years of age have prostate cancer. For advanced metastatic prostate cancer there is no cure, although therapy is available to control tumor growth, alleviate symptoms, and improve quality of life. Because androgens (primarily dihydrotestosterone) control the growth of the prostate gland, medical or surgical castration can cause regression of prostate cancer. Unfortunately, the response is often brief and prostate cancer continues to be a leading cause of death from cancer in men.

Goserelin acetate (Zoladex/Zeneca) is a medical alternative to surgical castration, and appears to be even more effective than removal of the testes for prolonging survival. An analog of luteinizing hormone-releasing hormone, goserelin inhibits pituitary gonadotropin secretion, which reduces testosterone to castration levels. Goserelin is given in combination with an antiandrogen to block any remaining testosterone anywhere in the body, particularly the adrenals. Side effects include hot flashes in about half of patients, and often impotence and loss of libido. Goserelin has been available as a 3.6-mg subcutaneous implant that releases goserelin continuously over 1 month; it is now also available in a 10.8-mg, 3-month implant. After absorption (rate of which depends on the implant used), goserelin undergoes hepatic metabolism and urinary excretion (more than 90% of a dose is excreted in the urine, and only 20% of this is as unchanged goserelin). Dosage adjustment is not required in elderly patients or in patients with renal or hepatic impairment. (Vogelzang NJ, et al. Urology. 1995;46:220-226. Additional information is available from the manufacturer.)

Another treatment option is radiation, delivered on an outpatient basis for 7 to 8 weeks by an external radiation machine (linear accelerator). Radiation is especially useful for cancers that have spread beyond the capsule of the prostate but are still confined to adjacent tissue. Side effects – which usually occur during the second half of a course of treatment and disappear with time – include diarrhea and urinary frequency, urgency, and discomfort. More than half of men become impotent (usually the older, less sexually active patients).

There is no doubt that prostate cancer is a major public health problem; yet only about 8% of cancers become clinically significant. What defines clinically significant cancer? According to Dugan et al, several factors should be considered when evaluating prostate cancer: patient age, life expectancy, grade (Gleason score), and cancer volume and volume-doubling time. There appears to be a continuum of prostate cancer; as the cancer volume increases, so does the malignant potential. Studies have shown that metastases are uncommon until a tumor reaches a size of about 3 cm3 and shows histologic evidence of higher malignant potential (higher Gleason grade). prostate-specific antigen and PSA-doubling time provide useful information about the growth rate of the cancer. Another important consideration is patient age. Prostate cancer in a young man will almost certainly progress to clinically significant cancer over his lifetime, according to Dugan, whereas the same cancer in an elderly man may not. He is more likely to die with prostate cancer than of it. (Dugan, et al. JAMA. 1996;275:288- 294.)

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The Prostate. Part 4

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Finasteride versus Terazosin for Benign Prostatic Hyperplasia

Results from a large clinical trial comparing the 5-alpha-reductase inhibitor finasteride with the alpha1-blocker terazosin for benign prostatic hyperplasia suggest that terazosin is the more effective of the two drugs. Abbott and Merck co-sponsored the 1-year study, which involved 1229 men randomly assigned to either finasteride, terazosin, a combination of the two, or placebo. Herbert Lepor (Chief of Urology at New York University Medical Center) reported the results at a recent meeting of the American Urological Association in Orlando, FL. Lepor said that finasteride was no more effective for reducing symptoms than placebo, whereas terazosin was significantly more effective than either finasteride or placebo. Only patients with large prostate glands that are nonresponsive to alpha1-blockade should be treated with finasteride, according to Lepor.

The report included an analysis of placebo-controlled trials as well as the comparison trial, comprising data on 2500 patients. Merck researchers responded that the size of the prostate gland in study participants (about 36 gm) was unusually small for a diagnosis of benign prostatic hyperplasia. Finasteride is most effective in men whose prostates weigh more than 40 gm (about half of men with BPH). The prostate normally weighs about 20 gm until a man reaches 40 years of age. Determining the relative efficacy of finasteride versus alpha1-blockers awaits the results of additional clinical trials. Currently, three studies are under way: an American trial of terazosin versus finasteride, a European trial of doxazosin versus finasteride, and a 5-year American trial of doxazosin versus finasteride. (American Urological Association meeting in Orlando, FL, 1996.)

Treating Benign Prostatic Hyperplasia with Microwaves

The first nonsurgical device for the treatment of benign prostatic hyperplasia has been approved by the FDA. This device – the Prostatron (produced by EDAP Technomed, Cambridge, MA) – uses microwaves to heat and destroy prostate tissue blocking the urethra. The Prostatron has a catheter that is inserted through the urethra to the prostate. The tip of the catheter acts as an antenna that emits microwaves to heat the tissue. Water circulates through the catheter applicator to cool the system and protect adjacent tissue. Although the Prostatron does not correct all problems (such as incomplete emptying of the bladder), the device is nevertheless an effective and convenient alternative to drug therapy (which provides only partial relief) and surgery (which is associated with complications such as impotence). Men with benign prostatic hyperplasia can be treated in about an hour in an outpatient setting. In European and American multicenter clinical trials involving 375 men with BPH, 75% reported symptomatic relief. Improvement was sustained in about half the patients at 4-year follow-up; however, the rest had to repeat the procedure or resort to drug therapy or surgery. (Information is available from the manufacturer.)

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The Prostate. Part 3

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Treating Benign Prostatic Hyperplasia with Finasteride

The androgens testosterone and dihydrotestosterone (DHT) control the development and function of the prostate gland. Testosterone is converted to DHT – the active androgen in many tissues, including prostate and skin – by the enzyme 5-alpha-reductase. Inhibiting 5-alpha-reductase markedly reduces prostate dihydrotestosterone, which decreases the size of the prostate in men with benign prostatic hyperplasia and improves urine flow. There are several 5-alpha-reductase inhibitors in clinical trial, one of which – finasteride (Proscar/Merck) – is approved in the United States for benign prostatic hyperplasia. There are two types of 5-alpha-reductase, and they are produced from different genes on different chromosomes and have different structures (there is only a 50% homology in amino acid sequence). Type 1 is found in all skin; type 2 is found mainly in genital skin. Finasteride blocks primarily type 2. It does not bind the androgen receptor, does not block other steroid hormones, and has no other hormonal effects.

With the recommended dosage of 5 mg once daily, finasteride reduces prostatic dihydrotestosterone by about 90%. The drug has a long biological half-life; DHT may not return to baseline for 2 weeks after finasteride is discontinued. Serum half-life is short by comparison (8 hours in elderly men and 6 hours in middle-aged men). Finasteride reduces semen volume by 25%, but has no effect on sperm count, motility, or morphology. The drug also reduces prostate-specific antigen by 50% in men with BPH within 3 months of initiating therapy. It appears to reduce prostate-specific antigen in men with prostate cancer, which raises concerns about whether finasteride may mask prostate cancer. The drug is excreted in urine and feces; no dosage reduction is necessary in elderly patients or in those with renal failure.

In a large clinical trial involving 895 men with benign prostatic hyperplasia treated for 1 year with finasteride (1 mg or 5 mg) or with placebo, prostate volume decreased by 18% and 19% in the 1-mg and 5-mg finasteride groups, respectively, while urinary flow increased by 22 to 23%. Overall symptoms improved in all three groups, but improvement was significant only in the 5-mg group. Merck recently won approval for labeling changes for finasteride to indicate that the drug works faster and in a greater percentage of patients than was previously thought. (Rittmaster RS. N Engl J Med. 1994;330:120-125. Additional information is available from the manufacturer.)

Treating Benign Prostatic Hyperplasia with Alpha1-blockers

Alpha1-adrenergic blocking agents were developed for the treatment of hypertension, but were found to relieve the symptoms of benign prostatic hyperplasia by relaxing muscles in the bladder and prostate. The first alpha1-blocker to receive FDA approval for benign prostatic hyperplasia was terazosin (Hytrin/Abbott), followed more recently by doxazosin (Cardura/Pfizer). Both drugs provide long- lasting relief of symptoms. In clinical studies of doxazosin involving more than 900 patients with BPH, the drug was significantly superior to placebo for improving symptoms and urinary flow rate. Relief was seen as early as 1 week after the initiation of therapy and was maintained for up to 2 years. In terazosin trials, the drug improved obstructive and irritative symptoms by more than 50% in 1483 men with benign prostatic hyperplasia.

Recently, a report was released describing a study of terazosin in 2,084 men (aged 55 and over) with severe benign prostatic hyperplasia, which is usually treated with surgery. The men were randomized to receive either terazosin (1053 men) or placebo (1031 men) and followed for one year. On average, symptom severity and quality of life were the same in both groups before treatment, but symptoms improved by 38% in patients in the terazosin group compared with 18% in the placebo group. Terazosin produced a 21% improvement in urinary flow compared to 7% with placebo. More patients withdrew from the placebo group because of lack of efficacy (25% withdrawal rate, compared with 11% in the terazosin group), but more withdrew from the terazosin group as the result of side effects (16%, compared with 11% in the placebo group). The most common side effects were dizziness and weakness.

Overall, improvement on terazosin was twice that with placebo. Although terazosin is usually prescribed for patients with moderate benign prostatic hyperplasia, results of this study suggest that drug therapy is an effective alternative to surgery for patients with severe BPH. The drug should also be considered for men with benign prostatic hyperplasia who have hypertension or are at risk for heart attack. A separate analysis of the data showed that 10 of 1031 men in the placebo group suffered heart attacks during the year of the study, compared with just one of 1053 men in the terazosin group. (Annual Meeting of the American Urological Association in Las Vegas, 1996.)

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