hi ed - i agree there are many variables that will add or substract from
the risks of developing pca.  green tea for example, is showing a strong
promise to prevent pca.  my brother is a good example of this.  weighing
in at 400 lbs, age 67, over 6'4" tall, and family history of prostate
cancer- each one of those facts that i mention is a risk factor - just
told me that his psa is .6  he drinks green tea throughout the day and
has for a long time.

a point to ponder is why they don't include dogs in all these studies
since they are the only animal that gets prostatitis and prostate cancer
naturally.

i did find many references to autopsies of men and evidence of prostate
cancer where it had not developed into a full blown case of pca.  i was
off on my number, it is actually higher.

here is just one of the references......

Stamey has stated that approximately 40% of men over the age of 50 will
show prostate cancer in autopsy studies, although only 8% of these
patients will develop prostate cancer clinically, and only 3% will die
from the disease. This disparity in growth rates and death rates had
lead to the controversy in prostate cancer as to who should be treated
and who should have observation only. These statistics are deceiving
because the great majority of men who have prostate cancer diagnosed
clinically in their lifetime under the age of 70 are at risk to die from
their disease. Generally individuals less than age 50 diagnosed to have
prostate cancer clinically (by digital rectal exam or elevated PSA) will
most likely die from the disease if untreated. At the other extreme, men
over the age of 70 will often do quite well with observation or hormone
treatments since the rate of growth of prostate cancer often will not
progress to a point resulting in prostate cancer death before heart
disease or other concurrent diseases will result in death. Because the
population is generally living longer,
prostate cancer is being diagnosed in a higher percentage of people.
Stamey has reported that the growth rate of prostate cancer is
astonishingly slow with half the cancers requiring over five years to
double in size. Stamey has stated that tumors under 5.5 cm cubed are
clinically insignificant, (1.0 cm cubed is about the size of a sugar
cube). If a tumor starts out at less than 0.5 cm cubed and the patient
is over 70 years of age, generally the paitent will not live long enough
to have the cancer increase in size in order to produce a significant
clinical problem. However, there are no good preoperatively or
nonoperatively ways to estimate prostate cancer size based on today's
technology including sonogram of the prostate, CAT scan of the prostate,
and MRI scan of the prostate.

PSA is a serine protease, a glycoprotein secreted by the epithelial
cells of the prostate gland. Prostate cancer, as it grows, distorts the
architecture of the prostate, spilling PSA into the bloodstream and
raising the level of PSA systemically. Chu Wang, in 1979, purified the
antigen from prostate tissue and named it prostate specific antigen.
Both normal prostate epithelial cells and hyperplastic prostate tissue
produce PSA, but not to the degree of malignant prostatic tissue.

Clinical vs Latent (autopsy) diagnosis:
It has been demonstrated that patients who have prostate cancer
diagnosed by PSA alone with normal rectal exams are at the same risk of
death from prostate cancer as patients who are diagnosed with a hard
prostate nodule by rectal exam. Other conditions can elevate the PSA
including infection, prostate enlargement, or any type of manipulation
of the prostate by catheter or cystoscopy. Furthermore, Proscar which is
commonly used to shrink the prostate, can reduce the level of PSA by
30-50% and must be taken into consideration when interpreting
PSA testing.

PSA Discovery:
In 1990 Christensson et al, discovered that PSA exists in more than one
circulating form in the serum. The free PSA (PSA-F), bound PSA (PSA-ACT)
and complexed PSA (PSA-MG) are all present in serum. In its complexed
form, the PSA-MG is not immunoreactive and is therefore not measured in
available commercial assays. Total PSA is generally measured from
commercial assays. This is combination of PSA-F and PSA-ACT. PSA-II
assay measures both total and free PSA. The percentage of free PSA is
lowered in patients with prostate cancer. This test can be ordered as a
further screening procedure to delineate prostate cancer from innocent
conditions that elevate the PSA. The higher the ratio of PSA-F to total
PSA, the less probability of cancer. With a cutoff at 20% of free to
total PSA, the ratio for sensitivity to diagnose cancer is 80%,
specificity is 49%, with a 95% confidence level. In other words, when
the free PSA falls below 20%, the patient is suspect to have prostate
cancer. The sensitivity of a test measures the capability of a test to
identify the presence of disease. A high sensitivity means very few
people with the disease are missed by the test. Specificity is the
capability of a test to identify the absence of disease (low false
positive) Therefore, the free PSA will pick up most patients with cancer
but will also identify some false positives (only 49% specificity). The
positive predictive value is the capability of a test to identify
patients with disease among all patients demonstrating positive results.

Screening:
Stamey maintains that most prostate cancers can be cured if they are
less than 6.0 cm cubed in size, but not greater than 12 cubic cm in
size. The usual recommendation is to have a rectal exam and PSA blood
test at least yearly starting at age 50, or age 40 if there is a family
history of prostate cancer or in African/American males where the risk
is higher. The risk of developing clinically important prostate cancer
in a man with a close family relative such as father or brother is about
twice that of men without a family history of prostate cancer, (16%
versus 8%). Benign prostatic enlargement will increase the PSA but only
about one tenth as much as the same volume of prostate cancer. In men
who have greater than 50 cubic cm of benign prostatic enlargement, PSA
produced can result in an elevation of serum PSA that may mask the rise
of PSA caused by cancer, especially if the cancer is in the small range.
This can complicate the work up and diagnosis of prostate cancer in this
group of patients. Fortunately most prostates are in the 25-35 gram
size.
Metastatic (Spread) Potential:
No one fully understands how prostate cancer escapes from the prostate
gland. All are in agreement that surgical cures from prostate cancer
require that the cancer be confined to the prostate before surgery. The
volume of cancer (size) and the grade of tumor (appearance of histology)
are important in evaluating a man for possible treatment modalities.
Prostate cancer is graded 1-5, based on the degree of differentiation of
the cancer. This is the architectural pattern of the cancer seen by
pathologists. As the cancer increases in size, the grade often increases
from 3 to 4 to 5. Grades 4 and 5 are poor prognostic indicators. The
Gleason's score is a combination of the two most prevalent grades in a
tumor. This is further used to separate patients into low and high risk
categories. In general, scores of 6 or less are good because it means
they have no grade 4 in their specimen, while 7 indicates a more
aggressive, higher grade tumor with some grade 4 being present. While
the PSA level, the grade of the tumor and the tumor size are all
important prognostic indicators, there is no preoperative test which
will absolutely determine whether the cancer is confined or not to the
prostate. Unfortunately, there are no preoperative modalities that will
absolutely define the exact extent of the cancer or the volume of the
cancer in the prostate. Various computer models have been designed based
on size of tumor, which is estimated from sonogram and biopsy, PSA
level, and grade of tumor, to determine the likelihood of metastatic
disease at the time of diagnosis. This helps the physician and patient
determine a treatment modality. Generally, PSA values less than 10,
prostate cancer volume less than 6 cubic cm and Gleason's score of less
than 6 are all favorable prognostic indicators, suggesting that a
radical prostatectomy may yield a cure. However, one third to one half
of patients who have undergone radical prostatectomy will have a
positive PSA 1-3 years following surgery, indicating that they have not
been cured of their underlying disease.

The above material represents a synthesis of 31 years of urology
practice plus residency, including many surgeries, patients encounters,
and continuing literature reviews. Each patient must educate themselves
thoroughly, consult with their Urologist, and make an informed decision
regarding treatment.
© Doctor Fetner.com
 

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
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