Benign Prostate Hyperplasia

What is benign prostate hyperplasia?

Benign prostate hyperplasia (BPH) is the noncancerous enlargement of the prostate gland, characterized by an increased number of cells in the ‘transition zone’ of the prostate.¹ It is considered a progressive disease as the prostate volumes of people with benign prostate hyperplasia tend to increase with each passing year, leading to more frequent and severe symptoms.²

Most of the time, "benign prostatic obstruction" (BPO) or "bladder outlet obstruction" (BOO) are used instead of "benign prostate hyperplasia" when the bladder is blocked and the urethra is pressed on. This can cause lower urinary tract symptoms (LUTS).

The absolute burden of benign prostatic hyperplasia is rising at an alarming rate in most of the world, particularly in low- and middle-income countries. Globally, there were 94 million cases of benign prostatic hyperplasia in 2019, almost double the number documented in the year 2000.³

^‍Current estimates are that at least 50% of men aged 60 years old have benign prostate hyperplasia, increasing to 80% to 90% of those older than 70 years of age.⁴

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Prognosis of benign prostate hyperplasia

Although benign prostate hyperplasia is a benign condition, it has been associated with lower urinary tract symptoms, bladder infections, decreased urinary flow, and reduced quality of life.⁵ Men with prostate sizes greater than 30 ml are 1.5 times more likely to suffer moderate to severe lower urinary tract symptoms than men with prostate sizes less than 30ml.⁶

When benign prostate hyperplasia is left untreated, it can also lead to the development of chronic high-pressure retention (a potentially life-threatening condition) and chronic changes to the bladder detrusor muscle.⁴

^‍In severe cases, it can even develop into complete urethral blockage, making people unable to pass urine (named acute urinary retention [AUR]). One study found that men with prostate sizes greater than 30 ml are 3 times more likely to experience acute urinary retention than men with prostate sizes <30 ml.⁶

Symptoms of benign prostate hyperplasia

Symptoms of benign prostate hyperplasia vary considerably from one person to another. Some men experience no symptoms, while others have mild-moderate or even severe symptoms. However, as people begin to age, and particularly if the prostate continues to enlarge, lower urinary tract symptoms are common.

On average, 50% of men over 60 years of age and 80% of men over 80 years of age experience lower urinary tract symptoms caused by benign prostate hyperplasia.⁷

The International Continence Society has categorised lower urinary tract symptoms into three groups, according to the three bladder cycle stages: storage (filling), voiding (emptying), and post micturition (immediately after voiding).⁸ The most common symptoms are presented in the table below.

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Diagnosis of benign prostate hyperplasia

Patients should be evaluated for benign prostate hyperplasia when they present with any complication related to urinary retention, recurrent or persistent urinary tract infections (UTIs), renal dysfunction, or a suspected malignancy.⁹

The oldest and perhaps simplest examination is the digital rectal examination (DRE), when a doctor checks inside the rectum with their finger to estimate whether prostate size is larger than expected.¹⁰‍

However, since digital rectal examination is not the most reliable indicator of actual size, a doctor should arrange for a more reliable diagnostic test if there are any concerns.¹¹

One increasingly common method of diagnosing benign prostate hyperplasia is by measuring the levels of a protein made in the prostate, called prostate-specific antigen (PSA). Unless influenced by other pathologic processes, PSA strongly correlates with prostate volume and is a predictor of prostate growth.^12,13

Normal PSA levels usually range from 0–4 ng/ml, with 4–10 ng/ml considered borderline high, while levels over 10 ng/ml are considered high. A PSA test may also be paired with a test of urine output, such as measuring how much urine that you can pass during urination (urinary flow test or a 24-hour voiding diary) and how much urine is left in the bladder after urination (postvoid residual volume test).

In more complex cases, other methods to diagnose benign prostate hyperplasia include:

• Transrectal ultrasound: A device that uses sound waves to make pictures is inserted into the rectum to measure the size of the prostate.
• Urodynamic and pressure flow studies: A catheter is threaded through the urethra into the bladder. Water or air is slowly sent into the bladder to measure bladder pressure and function during urination.
• Cystoscopy: A lighted, flexible tool is placed into the urethra to provide imaging inside the urethra and bladder.

Treatment of benign prostate hyperplasia

As benign prostate hyperplasia is a benign condition, watchful waiting (the regular monitoring of the prostate and symptoms), education, and lifestyle advice remain the first steps when the patient’s quality of life is not affected by the condition.

Lifestyle interventions that can be advised to manage benign prostate hyperplasia are to avoid alcohol and caffeine, to frequently consume water (with more water on hot days and when physically active), to use relaxation exercises and distraction techniques, and to self-monitor symptom changes.

In terms of medications, alpha-1 adrenergic receptor antagonists (A1Ras) provided the first licensed pharmacological therapy for benign prostate hyperplasia. These have been shown to effectively reduce smooth muscle tone to reduce resistance, improve flow rate and bladder emptying, and ultimately improve symptoms of the condition.²⁰

In clinical guidelines, the British Association of Urological Surgeons and the National Institute for Health and Clinical Excellence state that symptomatic men with relatively small prostates (<30 ml) and PSA levels <1.4ng/ml are best treated pharmacologically with an A1RA. Patients can expect a 20–30% improvement in symptoms within 6-12 weeks.^6,9

Along with A1Ras, treatment with phosphodiesterase 5 (PDE5) inhibitors or 5-alpha-reductase inhibitors may be considered in patients with predominantly voiding dysfunction. PDE5s have been demonstrated to increase blood supply to the prostate, suppress cell growth, and possibly reduce prostate inflammation.²¹

^‍5-alpha reductase inhibitors, on the other hand, inhibit the conversion of testosterone to the androgen needed for cell growth and division, dihydrotestosterone, which can help to shrink the prostate gland if it is enlarged.²²

In patients with predominantly storage symptoms and a post-void residual volume (PVR) below 150mL, the use of muscarinic receptor antagonists and ß3-adrenoceptor agonists is recommended. Both of these medications can increase bladder capacity by inhibiting contractions of and/or relaxing the detrusor muscle of the bladder. In turn, these effects may relieve symptoms of overactivity with no cholinergic or mental side effects.^4,24

In rare cases, when medical therapy fails to provide adequate symptom relief or is refused by the patient (relative indication for surgery), a healthcare professional may consider invasive treatment. This type of treatment is also an option if a patient presents with recurrent or refractory urinary retention, overflow incontinence, refractory macrohematuria, dilatation of the upper urinary tract with or without renal insufficiency, recurrent urinary tract infections, or bladder stones or diverticula (absolute indications for surgery).²⁴

If surgical procedures are warranted, transurethral resection of the prostate (TURP) and suprapubic enucleation procedures have been established as the gold standard in practice.²⁴

While TURP is mostly used for smaller and medium-sized prostate volumes (up to 80 ml), large adenomas are enucleated by open surgery.²⁴

‍It is important to note, however, that swift catheterization may be required if a patient has acute urinary retention (AUR), as this is considered a medical emergency that may result in renal failure.²⁵