Prostate Zones: BPH vs Cancer

Why one shouts and the other stays quiet · Week 14
The urethra runs straight through the prostate. BPH grows in the inner zone, right against that tube, so it blocks flow early. Cancer usually starts in the outer zone, so it stays quiet. Grow each zone and watch the stream, the PSA, and the exam.

A slice through the prostate

Looking down the urethra. The inner zone hugs the tube. The outer zone is the part a finger can reach on exam.
Inner zone, where BPH grows Outer zone, where cancer starts Tumor
Move a slider to begin.

Bladder and stream

The bladder wall thickens from pushing against the squeeze. Urine left behind is the residual volume.
Normal prostate20 g · stream open · PSA 1.0

Grow each zone

Inner zone growth — BPH0
Outer zone tumor0
Gland weight
20
g · about 20 normal
Urethra open
100
% of normal width
Peak flow
22
mL/s · over 15 normal
Left behind
0
mL after voiding
PSA
1.0
ng/mL · under 4 usual
On exam
smooth
what a finger feels
What is happening now
Grow the inner zone and watch the stream fall first.
PSA is a clue, not a verdict. Infection, a recent exam, ejaculation, and plain BPH can all raise it. A high or rising value earns a referral and often a biopsy. It does not earn a cancer label.