BPH stands for benign prostatic hyperplasia, the medical term for a non-cancerous enlargement of the prostate gland. It affects 50 to 75 percent of men over age 50, and that number climbs past 80 percent in men over 70. The word “benign” means it is not cancer, “prostatic” refers to the prostate, and “hyperplasia” means an increase in the number of cells. While BPH itself is not dangerous, the enlarged prostate can squeeze the urethra and make urination progressively more difficult.
Where the Growth Happens
The prostate is a walnut-sized gland that sits just below the bladder and wraps around the urethra, the tube that carries urine out of the body. BPH specifically develops in the transition zone, the inner ring of prostate tissue closest to the urethra. As cells multiply in this zone, the growing tissue presses inward against the urethra like a clamp, narrowing the channel and restricting urine flow.
Under a microscope, BPH tissue shows increased numbers of both glandular cells (which produce prostatic fluid) and stromal cells (the supportive connective tissue). Stromal cell growth is actually far more dramatic: one study found stromal proliferation was 37 times higher than in normal prostate tissue, while glandular proliferation was about 9 times higher. The stromal overgrowth also produces extra collagen, which stiffens the tissue and adds to the physical obstruction.
What Drives Prostate Enlargement
Two factors are required for BPH to develop: aging and male hormones (androgens). The key player is dihydrotestosterone, or DHT, a potent form of testosterone. Inside the prostate, an enzyme converts testosterone into DHT, which then stimulates both stromal and glandular cells to multiply. In a healthy prostate, new cell growth is balanced by old cells dying off. In BPH, that balance tips in favor of growth, and the gland slowly expands over years.
Hormones are not the whole story. Chronic inflammation, reduced blood flow to the prostate, oxidative stress, and metabolic conditions like obesity and diabetes all appear to contribute. This explains why some men still experience BPH progression even when treated with medications that lower DHT levels.
Symptoms of BPH
The symptoms caused by an enlarged prostate are collectively called lower urinary tract symptoms, or LUTS. They fall into two categories.
Voiding symptoms (related to getting urine out) include:
- Hesitancy: a delay before the stream starts
- Weak stream: reduced force or a thinner-than-normal flow
- Intermittent stream: flow that stops and starts
- Incomplete emptying: feeling like the bladder is not fully empty after urinating
- Dribbling: urine that continues to trickle after finishing
Storage symptoms (related to the bladder holding urine) include:
- Frequency: needing to urinate more often than usual
- Urgency: a sudden, strong need to urinate that is hard to postpone
- Nocturia: waking up multiple times during the night to urinate
Not every man with an enlarged prostate will have noticeable symptoms. Prostate size alone does not predict severity. Some men with modestly enlarged prostates have significant trouble urinating, while others with much larger glands have few complaints.
How Severity Is Measured
Doctors commonly use the International Prostate Symptom Score (IPSS), a seven-question survey that asks how often you experience each symptom. Scores range from 0 to 35: 0 to 7 is mild, 8 to 19 is moderate, and 20 to 35 is severe. Your score helps guide treatment decisions. Men with mild symptoms often do well with monitoring alone, while moderate to severe scores typically prompt a discussion about medication or procedures.
BPH and PSA Levels
Prostate-specific antigen (PSA) is a protein produced by prostate tissue, and BPH can raise your PSA level because a larger gland simply produces more of it. PSA levels above 1.5 ng/mL are commonly seen in men with prostate volumes over 30 mL. This overlap is important because elevated PSA is also used to screen for prostate cancer, meaning BPH can trigger a false alarm.
When PSA falls in the “grey zone” of 4.0 to 10.0 ng/mL, additional tests can help clarify the picture. One approach measures the ratio of free PSA to total PSA in the blood, which improves diagnostic accuracy by 15 to 20 percent. A newer measure called the Prostate Health Index combines multiple PSA markers and has been shown to outperform a standard PSA test in distinguishing BPH from cancer. If PSA is above 4 ng/mL, further evaluation, and potentially a biopsy, is typically recommended.
How BPH Differs From Prostate Cancer
BPH is not cancer and does not increase your risk of developing prostate cancer, though the two conditions can exist at the same time. BPH grows in the transition zone near the urethra, while prostate cancer more often arises in the peripheral (outer) zone. A digital rectal exam can sometimes detect differences in texture: BPH tends to feel smooth and rubbery, while cancerous areas may feel hard or irregular. Imaging with multiparametric MRI has become an increasingly common, non-invasive way to evaluate suspicious findings before deciding on a biopsy.
Medication Options
The two main classes of medication work through different mechanisms. The first type relaxes the smooth muscle fibers in the prostate and bladder neck, which eases the physical squeeze on the urethra. These medications typically improve urine flow within days to weeks. The second type lowers DHT levels in the prostate, which gradually shrinks the gland over several months. Roughly 30 to 50 percent of men respond to DHT-lowering medications. For men with both significant symptoms and a large prostate, the two types are sometimes combined.
Procedural Treatments
When medications are not enough or side effects are bothersome, several procedures can open up the blocked urethra. The traditional approach, transurethral resection of the prostate (TURP), involves removing excess prostate tissue through the urethra. It remains highly effective but carries risks of urinary incontinence, retrograde ejaculation (where semen goes into the bladder instead of out), and sexual dysfunction.
Newer, less invasive options have become widely available. One uses small permanent implants to physically lift and pin back the obstructing prostate lobes, opening the urethral channel without removing tissue. Another delivers steam into the prostate’s transition zone, which destroys excess tissue that the body then gradually reabsorbs. Both can often be performed as outpatient procedures under local anesthesia or light sedation. Five-year data show reintervention rates of about 7 percent for the steam-based approach and roughly 11 percent for the implant-based approach.
What Happens Without Treatment
Left untreated, BPH can progress beyond bothersome urination into more serious complications. Urinary retention, the inability to empty the bladder at all, can develop either suddenly (acute) or gradually (chronic). Chronic retention keeps the bladder under constant high pressure, which can transmit backward to the kidneys and cause hydronephrosis, a swelling of the kidneys that, over time, leads to kidney damage.
Stagnant urine in the bladder also creates a breeding ground for recurrent urinary tract infections. Minerals in that pooled urine can crystallize into bladder stones, which account for about 5 percent of all urinary tract stones and are strongly associated with bladder outlet obstruction. Chronic retention with recurrent infections is itself a predictor of long-term kidney decline. Upper urinary tract dilation or elevated creatinine levels have been found in half of all patients with chronic retention caused by BPH.
These complications develop gradually, which is why periodic monitoring matters even for men whose symptoms start out mild. A noticeable worsening in stream strength, a sudden inability to urinate, or blood in the urine are signs that the condition may be advancing beyond what watchful waiting can safely manage.