What actually happens when the prostate grows

Most men reach fifty knowing the prostate exists and very little else about it. That is a shame, because the mechanics of what goes wrong are simple enough to explain in a couple of minutes, and knowing them makes the symptoms far less frightening.

Where it sits, and why that matters

The prostate is a gland about the size of a walnut, sitting just below the bladder. Its job is to produce part of the fluid that carries sperm.

The detail that explains almost everything else is this: the urethra, the tube that carries urine out of the bladder, runs straight through the middle of it. No other gland in the body is arranged this way. It means that when the prostate grows, it grows around a pipe — and the pipe is the one you use every time you go to the bathroom.

The two growth periods

The prostate grows twice in a man's life. The first is at puberty, when it roughly doubles in size and then settles. The second begins around the age of twenty-five and continues, slowly, for the rest of your life.

That second phase is why this is a condition of age rather than of bad luck. By sixty, most men have some degree of enlargement. It is called benign prostatic hyperplasia — benign meaning it is not cancer, hyperplasia meaning more cells rather than abnormal ones.

Why the symptoms take the shape they do

Squeeze a garden hose and two things happen: less water comes out, and pressure builds behind the squeeze. The bladder faces the same problem, and the symptoms divide neatly along those lines.

• Getting urine out. A weaker stream, a delay before it starts, stopping and starting, dribbling at the end, and the sense that the bladder is not empty afterwards.
• Storing urine. Going more often, sudden urgency, and getting up at night. These come later, as the bladder muscle thickens from working against the resistance and becomes irritable.

This is also why size and symptoms match up so poorly. A modest prostate pressing centrally can cause more trouble than a large one growing outwards. Men are often surprised to hear that the gram figure on their ultrasound report predicts their discomfort rather badly.

What is worth knowing

Benign enlargement and prostate cancer are different conditions. Having one does not mean you have the other, and the symptoms above are not, by themselves, signs of cancer.

What they are signs of is something worth having looked at. Symptoms that are ignored for years can end in a bladder that has been straining so long it stops emptying properly — and that is a harder problem than the one you started with.

This article is general information about how the prostate works. It is not medical advice and does not replace an assessment by your doctor.