Hello again Filw,
First, how kind of you to be concerned for your father's health!
An elevated blood serum PSA and/or prostatic hypertrophy
(excessive growth of prostate tissue) are good predictors of cancer.
The next step is a prostate biopsy. As in many things medical, a
prostate biopsy is not 100% accurate, as a cancerous area of tissue
may be missed. If enough samples are taken, however, along with
indicative symptoms, blood tests and a digital rectal exam (DRE), a
urologist will have as good of an indication as possible. Some
urologists use an ultra-sound guided biopsy technique to locate
sampling areas.
?The calculator -- posted online for use by both patients and
physicians -- adds age, race, family history of prostate cancer, prior
biopsy findings, and digital rectal exam (DRE) results into the mix
alongside PSA levels, to assess a man's risk before having a new
biopsy.
"PSA is a very important predictor of cancer, but is only one part of
the picture of a man's risk of cancer," explained study author Dr. Ian
M. Thompson, professor and chairman of the department of urology at
the University of Texas Health Science Center in San Antonio.?
http://www.medicinenet.com/script/main/art.asp?articlekey=61133
?After analysis the most important factors that were associated
with positive biopsy (prostate cancer) were PSA, prostate gland
volume, DRE, ultrasound findings, and a history of prior biopsy. These
factors were then used in a mathematical model to predict the
likelihood of an individual having biopsy proven prostate cancer.?
http://www.cancernews.com/category.asp?Cat=20&AID=230
?Trans Rectal Ultrasound Scans use sound waves to make an image of
the prostate. This is shown on a screen similar to a small television.
The scan allows the specialist to measure the size of the prostate and
helps them to guide the biopsy needles.
What happens at the biopsy appointment?
The biopsy will be taken either by the urologist, a radiologist, or a
specialist nurse who is trained in the use of ultrasound. The
ultrasound probe is lubricated with gel and passed into your back
passage (rectum). The probe is the size of a very fat finger and
should not feel any more uncomfortable than the DRE. The needle is
then placed down the shaft of the probe and is passed through the wall
of the back passage into the prostate gland, under the guidance of the
ultrasound image.?
http://www.prostate-cancer.org.uk/info/tests_trus.asp
This WebMD site explains the different types of biopsy procedures:
?For a prostate biopsy, a thin needle is inserted through the rectum
(transrectal biopsy), through the urethra, or through the area between
the anus and scrotum (perineum). A transrectal biopsy is the most
common method used. The tissue samples taken during the biopsy are
examined for cancer cells.?
?Almost all pathologists grade prostate cancers according to the
Gleason system. This system assigns a Gleason grade, using numbers
from 1 to 5 based on how much the arrangement of cells in the
cancerous tissue looks like normal prostate tissue.
?If the cancerous tissue looks much like normal prostate tissue, a
grade of 1 is assigned.
?If the cancer lacks these features and its cells seem to be spread
haphazardly through the prostate, it is called a grade 5 tumor.
?Grades 2 through 4 have intermediate features.
Because prostate cancers often have areas with different grades, a
grade is assigned to the 2 areas that make up most of the cancer.
These 2 grades are added together to yield the Gleason score (also
called the Gleason sum) between 2 and 10. The higher your Gleason
score, the more likely it is that your cancer will grow and spread
rapidly.? Again, please read the web site below for complete
information.
http://www.webmd.com/hw/mens_conditions/hw5468.asp
?Several biopsy samples are often taken from different areas of the
prostate. Anywhere from 6 to 13 samples are usually needed to check if
cancer is present and to see how much of the gland is affected. But as
many as 24 samples may be taken from some patients. You may want to
discuss the number of biopsies to be taken with your doctor before the
procedure starts.
Unfortunately, even when taking many samples, biopsies can still
sometimes miss detecting cancer if none of the biopsy needles pass
through it. This is known as a "false negative" result. If your doctor
still strongly suspects you may have prostate cancer (due to a very
high PSA level, for example) a repeat biopsy may be needed to help
rule this out.?
http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_prostate_cancer_diagnosed_36.asp?sitearea=
Note that the AUS (American Urologic Association) recommends 10-12
site samples during a biopsy:
?Despite taking more samples at the time of biopsy it is estimated
that about 30% of the time cancer is missed on the first biopsy (2).
This means that many men will require second prostate biopsies, at the
discretion of their physician, and further patient anxiety may result.
In fact, it has been estimated that more than one million prostate
biopsies are performed annually in an attempt to diagnose prostate
cancer.?
?Prostate screening can produce significant anxiety among men. This is
due, in part, to the uncertain nature of the outcome. While
abnormalities in the physical exam (DRE) and the PSA may tell the
physician that more tests need to be done to look for prostate cancer,
their ability to predict the chance of a patient actually having
prostate cancer is limited. The authors recognize the level of patient
anxiety and understand the pitfalls of trying to give the patient a
sense of his particular chance of having prostate cancer at the time
of biopsy. For this reason the authors have collected information from
over 300 men undergoing prostate biopsy. Our goal was to construct a
mathematical model that can offer the patient an accurate estimate of
his chances of having a positive prostate biopsy.
For the physician to diagnose prostate cancer a biopsy of the prostate
must be performed. This test is done on patients that have either an
abnormal PSA or DRE, or on patients that have had previous biopsies,
with findings that lead the physician to recommend another biopsy.
Biopsy of the prostate requires guidance by transrectal ultrasound
(TRUS). Recently it has been found that between 10 and 12 biopsy
samples should be taken per patient, so that the doctor has the best
chance of finding the cancer. Despite taking more samples at the time
of biopsy it is estimated that about 30% of the time cancer is missed
on the first biopsy (2). This means that many men will require second
prostate biopsies, at the discretion of their physician, and further
patient anxiety may result. In fact, it has been estimated that more
than one million prostate biopsies are performed annually in an
attempt to diagnose prostate cancer.?
http://www.cancernews.com/category.asp?Cat=20&AID=230
?The Gleason score, the most widespread method of prostate cancer
tissue grading used today, is the single most important prognostic
factor in PC.1-7 It is one determinant of a patient?s specific risk of
dying due to prostate cancer. 2,8 Hence, once the diagnosis of
prostate cancer is made on biopsy, tumor grading, especially the
Gleason score, strongly influences decisions regarding options for
therapy.?
?Systematic prostate biopsy labeling provides additional clinical
information of value in the risk assessment of the patient.16
Anatomic, site specific, biopsy labeling or ?prostate biopsy mapping?
allows for (1) determination of the total percentage of separate
biopsy samples involved by cancer (i.e. often referred to as ?the
percentage of positive cores?),17-21 (2) the measurement in mm?s of
the amount (or the percentage) of linear involvement by PC present in
each positive biopsy core at a particular biopsy site,22-25 and (3)
the anatomic region or zone of origin (transition zone vs. peripheral
zone) of PC involvement? Please read this entire site for in-depth
information on Gleason scoring and prostate biopsy.
http://www.prostate-cancer.org/education/staging/Dowd_GleasonScore.html
?Factors that were predictive of high-grade prostate cancer were a
higher PSA level, an abnormal DRE, older age at biopsy, and African
American race; a prior negative biopsy reduced this risk. PSA velocity
was not an independent risk predictor of either prostate cancer or
high-grade disease, and age at prostate biopsy was not a predictor of
prostate cancer. The data indicate that PSA level is such a strong
predictor of prostate cancer that neither age nor the rate at which
the PSA level rises is important.?
http://jncicancerspectrum.oxfordjournals.org/cgi/content/full/jnci;98/8/506
Gleason score and biopsies:
http://psa-rising.com/caplinks/medical_biopsy.htm
Again, if anything is unclear, please request an Answer
Clarification, and allow me to respond, before you rate this answer.
Sincerely, Crabcakes
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prostate biopsy + predictor
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