Benign prostatic hyperplasia: Evaluation and medical management in primary care

Prostate-specific antigen

Prostate-specific antigen (PSA) is a glycoprotein primarily produced by prostatic luminal epithelial cells. It is most commonly discussed in the setting of prostate cancer screening, but its utility extends to guiding the management of BPH.

PSA levels correlate with prostate volume and subsequent growth.¹¹ In addition, the risks of developing acute urinary retention or needing surgical intervention rise with increasing PSA.¹² Among men in the Proscar Long-Term Efficacy and Safety Study, the risk of acute urinary retention or BPH-related surgery after 4 years in the watchful-waiting arm was 7.8% in men with a PSA of 1.3 ng/dL or less, compared with 19.9% in men with a PSA greater than 3.2 ng/dL.¹¹ Therefore, men with BPH and an elevated PSA are at higher risk with watchful waiting and may be better served with medical therapy.

In addition, American Urological Association guidelines recommend measuring serum PSA levels in men with a life expectancy greater than 10 years in whom the diagnosis of prostate cancer would alter management.¹⁰

Urologic referral

If the initial evaluation reveals hematuria, recurrent urinary tract infection, a palpable bladder, abnormal findings on digital rectal examination suggesting prostate cancer, or a history of or risk factors for urethral stricture or neurologic disease, the patient should be referred to a urologist for further evaluation (Table 1).¹⁰ Other patients who should undergo urologic evaluation are those with persistent bothersome symptoms after basic management and those who desire referral.

Adjunctive tests

Patients referred for urologic evaluation may require additional tests for diagnosis and to guide management.

Postvoid residual volume is easily measured with either abdominal ultrasonography or catheterization and is often included in the urologic evaluation of BPH. Patients vary considerably in their residual volume, which correlates poorly with BPH, symptom severity, or surgical success. However, those with a residual volume of more than 100 mL have a slightly higher rate of failure with watchful waiting.¹³ Postvoid residual volume is not routinely monitored in patients with a low residual volume unless there is a significant change in urinary symptoms. Conversely, patients with a volume greater than 200 mL should be monitored closely for worsening urinary retention, especially if considering anticholinergic therapy.

There is no absolute threshold postvoid residual volume above which therapy is mandatory. Rather, the decision to intervene is based on symptom severity and whether sequelae of urinary retention (eg, incontinence, urinary tract infection, hematuria, hydronephrosis, renal dysfunction) are present.

Uroflowmetry is a noninvasive test measuring the urinary flow rate during voiding and is recommended during specialist evaluation of men with lower urinary tract symptoms and suspected BPH.¹⁰ Though a diminished urinary flow rate may be detected in men with bladder outlet obstruction from BPH, it cannot differentiate obstruction from detrusor underactivity, both of which may result in reduced urinary flow. Urodynamic studies can help differentiate between these two mechanisms of lower urinary tract symptoms. Uroflowmetry may be useful in selecting surgical candidates, as patients with a maximum urinary flow rate of 15 mL/second or greater have been shown to have lower rates of surgical success.¹⁴

Urodynamic studies. If the diagnosis of bladder outlet obstruction remains in doubt, urodynamic studies can differentiate obstruction from detrusor underactivity. Urodynamic studies allow simultaneous measurement of urinary flow and detrusor pressure, differentiating between obstruction (manifesting as diminished urinary flow with normal or elevated detrusor pressure) and detrusor underactivity (diminished urinary flow with diminished detrusor pressure). Nomograms¹⁵ and the easily calculated bladder outlet obstruction index¹⁶ are simple tools used to differentiate these two causes of diminished urinary flow.

Cystourethroscopy is not recommended for routine evaluation of BPH. Indications for cystourethroscopy include hematuria and the presence of a risk factor for urethral stricture disease such as urethritis, prior urethral instrumentation, or perineal trauma. Cystourethroscopy can also aid in surgical planning when intervention is considered.

An algorithm for diagnostic workup and management of BPH and lower urinary tract symptoms is shown in Figure 3.¹⁷

MANAGEMENT STRATEGIES FOR BPH

While BPH is rarely life-threatening, it can significantly detract from a patient’s quality of life. The goal of treatment is not only to alleviate bothersome symptoms, but also to prevent disease progression and disease-related complications.

BPH tends to progress

Understanding the natural history of BPH is imperative to appropriately counsel patients on management options, which include watchful waiting, behavioral modification, pharmacologic therapy, and surgery.

In a randomized trial,¹⁸ men with moderately symptomatic BPH underwent either surgery or, in the control group, watchful waiting. At 5 years, the failure rate was 21% with watchful waiting vs 10% with surgery (P < .0004). (Failure was defined as a composite of death, repeated or intractable urinary retention, residual urine volume > 350 mL, development of bladder calculus, new persistent incontinence requiring use of a pad or other incontinence device, symptom score in the severe range [> 24 at 1 visit or score of 21 or higher at two consecutive visits, with 27 being the maximum score], or a doubling of baseline serum creatinine.) In the watchful-waiting group, 36% of the men crossed over to surgery. Men with more bothersome symptoms at enrollment were at higher risk of progressing to surgery.

In a longitudinal study of men with BPH and mild symptoms (IPSS < 8), the risk of progression to moderate or severe symptoms (IPPS ≥ 8) was 31% at 4 years.¹⁹

The Olmsted County Study of Urinary Symptoms and Health Status Among Men²⁰ found that the peak urinary flow rate decreased by a mean of 2.1% per year, declining faster in older men who had a lower peak flow at baseline. In this cohort, the IPSS increased by a mean of 0.18 points per year, with a greater increase in older men.²¹

Though men managed with watchful waiting are at no higher risk of death or renal failure than men managed surgically,¹⁷ population-based studies have demonstrated an overall risk of acute urinary retention of 6.8/1,000 person-years with watchful waiting. Older men with a larger prostate, higher symptom score, and lower peak urinary flow rate are at higher risk of acute urinary retention and progression to needing BPH treatment.^22,23

There is evidence that patients progressing to needing surgery after an initial period of watchful waiting have worse surgical outcomes than men managed surgically at the onset.¹⁸ This observation must be considered in counseling and selecting patients for watchful waiting. Ideal candidates include patients who have mild or moderate symptoms that cause little bother.¹⁰ Patients electing watchful waiting warrant annual follow-up including history, physical examination, and symptom assessment with the IPSS.

Behavioral modification

Behavioral modification should be incorporated into whichever management strategy a patient elects. Such modifications include:

• Reducing total or evening fluid intake for patients with urinary frequency or nocturia.
• Minimizing consumption of bladder irritants such as alcohol and caffeine, which exacerbate storage symptoms.
• Smoking cessation counseling.
• For patients with lower extremity edema who complain of nocturia, using compression stockings or elevating their legs in the afternoon to mobilize lower extremity edema and promote diuresis before going to sleep. If these measures fail, initiating or increasing the dose of a diuretic should be considered. Patients on diuretic therapy with nocturnal lower urinary tract symptoms should be instructed to take diuretics in the morning and early afternoon to avoid diuresis just before bed.