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Prostate
cancer is a group of cancerous cells (a malignant tumor) that begins
most often in the outer part of the prostate. It is the most common type
of cancer (excluding skin cancer) diagnosed in American men. In 2003, an
estimated 220,900 new cases of prostate cancer will be diagnosed in the
U.S.
Early
prostate cancer usually does not cause any symptoms. However, as the
tumor grows, it may spread from the prostate to surrounding areas.
Change in urination, including increased frequency, hesitancy or
dribbling of urine may be experienced.
Prostate
cancer can spread from the prostate to nearby lymph nodes, bones or
other organs. This spread is called metastasis. For example, as a result
of metastasis to the spine, some men experience back pain.
The
overall prognosis for prostate cancer patients has dramatically
improved compared with years ago. Over the past 20 years, the overall
survival rates for all stages of prostate cancer combined have increased
from 67% to 97%. This means more men are living longer after diagnosis.
Some of the
possible reasons for this increase in survival rates include public
awareness and early detection. Click
here to learn more about detection methods.
WHAT
CAUSES PROSTATE CANCER?
While
researchers still do not know the exact answer to this question, they
have identified some risk factors.
As you grow
older, your chance of having a diagnosis of prostate cancer increases.
In fact, we believe that one of the reasons that prostate cancer is now
so much more common than it was 50 years ago is very obvious: more men
live longer today than they did 50 years ago. If you live longer, your
chance of having a diagnosis of prostate cancer goes up proportionally.
There are
some studies, based on post mortem findings, estimating that all men
would have prostate cancer if they all lived to over a hundred.
The average age of men diagnosed with prostate cancer in America is
still over 60 years (although diagnosis in younger men is much more
common than it used to be). And the range of ages is very wide. Cases of
prostate cancer have first been seen in men in their twenties and in men
in their nineties.
Family history
Generally speaking, men with a father or brother diagnosed with prostate
cancer at a relatively young age are at a greater risk of getting the
disease themselves, compared to the average man. Having an elderly
relative with prostate cancer is not uncommon and doesn't increase
risk.
The risk appears to be higher if you have a brother with prostate cancer
than it is if you have a father with prostate cancer. The risk is
higher still if you have more than one relative diagnosed with prostate
cancer.
It is important to remember that statistics are always a
generalization. There are likely to be specific factors at work for
some men, which increase their risk. Others not affected by these
factors may not have an increased risk, despite having a relative with
prostate cancer.
The reason risk is greater if your family member was young when
diagnosed or if you have several relatives with prostate cancer is that
these are signs that there could be a faulty gene running in the
family. The younger the age at diagnosis, the more likely it is that a
faulty gene is at work. Remember - for there to be a gene at work, the
affected relatives have to come from the same side of your family (your
mother's side or your father's side). There is no gene test because
specific faulty genes for prostate cancer haven't been clearly
identified yet.
Families that carry the breast cancer genes BRCA1 and BRCA2 also have an
increased risk of prostate cancer. We now know that men who carry the
BRCA1 gene have almost twice the risk of getting prostate cancer before
the age of 65, when compared with the average man under 65. This sounds
dramatic, but the risk of prostate cancer under 65 years is relatively
low. Once you are over 65, the risk of prostate cancer is the same as
any man over 65.
For the BRCA2 gene, the risks are higher. If you carry this gene, you
have 7 times the risk of getting prostate cancer before you are 65, when
compared with the average man under 65. Once you are over 65, you have
4.5 times the risk of prostate cancer if you carry this gene, when
compared to the average man over 65.
Race
Prostate cancer is much more common in some races than in others. For
example, Japanese men living in Japan have an extremely low incidence of
prostate cancer. By comparison African American men are at very high
risk of this disease.
The death
rate for prostate cancer is more than 2 times higher in African-American
men than in Caucasian/Asian men.
Why is this?
We don't know. What we do know is that it isn't just about their
genetics and heritage, because men of Japanese origin living in America
have a similar risk of prostate cancer as any other average American man
living in the same area! However, race can be an important factor in
determining when a man should have a
prostate-specific antigen (PSA)
blood test and
digital rectal exam (DRE)
once every year
for signs of prostate cancer.
Environment
The cleaner
your environment the less likely you are to be at risk of prostate
cancer. But then that is true for nearly all cancers, and explains why
smoking is such a particularly foolish thing to do if you want to avoid
cancer. Smoking introduces pollutants directly into your lungs, and from
there to almost every other organ of the body. You might as well go and
stand beside the nearest major freeway and inhale car and truck exhaust
fumes all day! Once again, however, there is no perfectly clean
environment that will allow you to live without the risk of prostate
cancer!
Diet
There is a lot of talk about diet and prostate cancer risk. But we all
eat such a variety of different things that any association between diet
and illness is very difficult to prove.
Two new studies, both in the
February 2004 Journal of Clinical Oncology, examine this
relationship between obesity and prostate cancer recurrence.
A very large Europe wide research study is looking
into diet and several different types of cancer, including prostate
cancer. Thousands of people are taking part and recording what they eat
and drink. The researchers will follow their progress for more than 10
years and see who gets what.
As with many other cancers, we think that a diet high in animal fat and
low in fresh fruit and vegetables may increase your risk. Tomatoes and
tomato products in particular may help protect against prostate cancer.
Tomatoes contain something called 'lycopene'. This is a carotenoid,
meaning that it is similar to vitamin A. Lycopene has now been
associated with blood levels of a chemical called
IGF-1 and prostate cancer risk.
(Click here for more information about
diet).
Insulin-like
growth factor is a normal chemical that we all make. It is involved in
the regulation of normal cell life, growth and death. There is a strong
link between levels of this chemical in the blood and prostate cancer
risk.
This research is still in the early stages and it is still a bit
'chicken and egg' at the moment. Some researchers think that IGF-1
might help to cause prostate cancer. Others think it might be made by
prostate cancer cells, higher levels meaning you already have the
disease - so they think it is a marker for cancer, like PSA.
What we do know is that several things affect the level of IGF-1 in your
blood. Low fat diet, eating fewer calories, lycopene, eating tomatoes
and strenuous exercise can all lower IGG-1 levels. A lot of milk,
dairy products, calcium and polyunsaturated fat in your diet all
increase IGF-1 levels.
Hormones
The prostate gland is a sex organ. It produces a liquid which is mixed
with sperm to form semen.
Testosterone is a sex hormone produced by the testicles. The prostate
gland needs testosterone to work, but testosterone may help to cause
prostate cancer. Men who lose both testicles early in life, and who
don't have testosterone replacement do not
get prostate cancer.
Prostate cancer cells need testosterone to grow. If testosterone is
prevented from getting to the prostate cancer cells, then they can often
shrink the cancer.
Vasectomy
One question
that crops up over and over again is whether having a vasectomy (the
procedure that stops a man from making a woman pregnant) can lead to a
later diagnosis of prostate cancer.
First of all, it has to be said that men who have vasectomies do
appear to be more likely to have a diagnosis of prostate cancer 20 years
later than men who do not have vasectomies. However, it also has
to be said that there is absolutely no evidence whatsoever of a cause
and effect relationship. Indeed, there is good reason to believe that
this is a statistical coincidence that has to do with the attitudes to
health of men most likely to have vasectomies.
Basically, men who have vasectomies exhibit what is widely described as
"health-seeking" behavior. In other words, they are the type of men who
look after their health, tend to go for regular check-ups, and generally
have a lifestyle which could be considered as "healthy." They are
presumed to be more likely to have vasectomies because they have
considered that the risks associated with a vasectomy are far lower than
the risks associated with their wife/partner having a late or unwanted
pregnancy.
Now it is also reasonable to suppose that men who exhibit health-seeking
behavior are more likely to seek regular prostate examinations as part
of that behavior. This immediately implies that the same men who seek
vasectomies are more likely to have a prostate examination than the men
who do not have vasectomies. Therefore these men are more likely to be
diagnosed with prostate cancer!
The bottom line is that men who have vasectomies are somewhere between
1.5 and 2.0 times more likely to have a later diagnosis of prostate
cancer than men who have not had a vasectomy ... but that we have no
reason to believe that there is any connection between the two.
ARE ALL CASES OF PROSTATE CANCER EQUAL IN RISK?
Bluntly, no
they aren't. One of the most infuriating problems is that for many men a
diagnosis of prostate cancer is not significant! If you look at the
prostates taken from 100 American men over 50 years old who die in car
crashes and similar accidents, that is men who never showed any clinical
sign of prostate cancer while they were alive, you can, in fact, find
small areas of cancer in the prostates of about 30 of those men (30%).
Those men could have lived for years with those small areas (foci) of
prostate cancer -- or some of them could have been diagnosed with
clinically significant prostate cancer just a few months later if they
had lived. If you do the same thing with American men over 90 years old,
you find that 90% of them have microscopic evidence of prostate cancer.
These small areas of prostate cancer tissue that do not develop into
clinically important disease are often called "latent" prostate cancer.
For an average American man of 50 years of age, with a reasonable life
expectancy of another 25 years, the chance that he will develop a
microscopic focus of so-called "latent" prostate cancer tissue is
estimated to be 42% (that is, 42 of 100 such men will get such a
microscopic focus). However, the chance that the same man will get
clinically significant prostate cancer (that is, prostate cancer that is
associated with clear signs or symptoms of the disease) is only 9.5%.
Finally, of the same 100 men, only about three will actually die of
prostate cancer. So you can clearly see that while many men may get
prostate cancer, it will actually affect relatively few of them very
seriously. It is often said that most men are much more likely to die
with prostate cancer than because of this disease.
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10 Facts about
Prostate Cancer
All prostate cancer incidence and
death numbers are 2004 estimates by the American Cancer Society.
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One in every six men
will get prostate cancer sometime in his life.
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The chances of getting
prostate cancer are 1 in 3 if you have just one
close relative (father, brother) with the
disease. The risk is five-fold with two close
relatives. With three, it’s almost certainty (97 %)
that you’ll get prostate cancer.
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African American men are
at special risk for the disease. They have the highest
rate of prostate cancer in the world. In fact, the
incidence rate in African Americans is 60 % higher
than in white males and double the mortality rate.
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Prostate cancer is the
second leading cause o
f male cancer death in the
United States. An American man dies every 18
minutes from the disease.
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An estimated 29,900
men will die from prostate cancer this year.
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More than 230,000
cases are expected this year – more than breast
cancer.
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Research shows that
obesity is a significant predictor of prostate cancer
occurrence and death. Men with a body mass over
32.5 have about one-third greater risk of dying from
prostate cancer.
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Before the advent of early
detection through PSA screening, about three-fourths of
all prostate cancer cases were found in the late stages
where the disease isn’t readily treatable or curable.
Since widespread use of screening , about
three-fourths of all case are now found early –
giving men a fighting chance.
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Every man over 50 – younger if African American or with a family history of the disease –
should resolve to be screened annually for
prostate cancer.
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Screening
for prostate cancer takes less than 10 minutes
and is covered by health insurance in many
states |
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