|
The prostate
The prostate is a gland found only in men. As shown in the
picture below, the prostate is just below the bladder and in front of
the rectum. It is about the size of a walnut. The tube that carries
urine (the urethra) runs through the prostate. The prostate contains
cells that make some of the fluid (semen) that protects and nourishes
the sperm.
The prostate begins to develop before birth and keeps on
growing until a man reaches adulthood. Male hormones (called androgens)
cause this growth. If male hormone levels are low, the prostate gland
will not grow to full size. In older men, though, the part of the
prostate around the urethra may keep on growing. This causes BPH
(benign prostatic hyperplasia) which can result in problems passing
urine. BPH is a problem that must be treated, but it is not cancer.
Prostate cancer
There are several cell types in the prostate, but nearly all
prostate cancers start in the gland cells. This kind of cancer is known
as adenocarcinoma. The rest of the information here refers only to
prostate adenocarcinoma.
Most of the time, prostate cancer grows slowly. Autopsy
studies show that many older men (and even younger men) who died of
other diseases also had prostate cancer that never caused a problem
during their lives. These studies showed that as many as 7 to 9 out of
10 men had prostate cancer by age 80. But neither they nor their
doctors even knew they had it.
Pre-cancerous changes of the prostate
Some doctors believe that prostate cancer begins with very
small changes in the size and shape of the prostate gland cells. These
changes are known as PIN (prostatic intraepithelial neoplasia). Almost
half of all men have PIN by the time they reach 50. In PIN, there are
changes in how the prostate gland cells look under the microscope, but
the cells are basically still in place -- they don't look like they've
gone into other parts of the prostate (like cancer cells would). These
changes can be either low-grade (almost normal) or high-grade
(abnormal).
If you have had a prostate biopsy that showed high-grade PIN,
there is a greater chance that there are cancer cells in your prostate.
For this reason, you will be watched carefully and may need another
biopsy.
Last Medical Review: 09/26/2008
Last Revised: 09/26/2008
|
