Prostate cancer is a disease which only affects
men. Cancer begins to grow in the prostate - a
gland in the male reproductive system.
The word "prostate" comes from Medieval
Latin prostate and Medieval French prostate .
The ancient Greek word prostates means "one
standing in front", from proistanai meaning
"set before". The prostate is so called because
of its position - it is at the base of the
bladder.
What is the prostate ?
The prostate is an exocrine gland of the male
reproductive system, and exists directly under
the bladder, in front of the rectum. An exocrine
gland is one whose secretions end up outside
the body e.g. prostate gland and sweat
glands. It is approximately the size of a
walnut.
The urethra - a tube that goes from the
bladder to the end of the penis and carries
urine and semen out of the body - goes
through the prostate.
There are thousands of tiny glands in the
prostate - they all produce a fluid that forms
part of the semen. This fluid also protects and
nourishes the sperm. When a male has an
orgasm the seminal-vesicles secrete a milky
liquid in which the semen travels. The liquid is
produced in the prostate gland, while the
sperm is kept and produced in the testicles.
When a male climaxes (has an orgasm)
contractions force the prostate to secrete this
fluid into the urethra and leave the body
through the penis.
Urine control
As the urethra goes through the prostate: the
prostate gland is also involved in urine control
(continence) with the use of prostate muscle
fibers. These muscle fibers in the prostate
contract and release, controlling the flow of
urine flowing through the urethra.
The Prostate Produces Prostate-specific
antigen (PSA)
The epithelial cells in the prostate gland
produce a protein called PSA (prostate-
specific antigen). The PSA helps keep the
semen in its liquid state. Some of the PSA
escapes into the bloodstream. We can
measure a man's PSA levels by checking his
blood. If a man's levels of PSA are high, it
might be an indication of either prostate
cancer or some kind of prostate condition. It is a myth to think that a high blood-PSA
level is harmful to you - it is not. High blood
PSA levels are however an indication that
something may be wrong in the prostate.
Male hormones affect the growth of the
prostate, and also how much PSA the prostate
produces. Medications aimed at altering male
hormone levels may affect PSA blood levels. If
male hormones are low during a male's
growth and during his adulthood, his prostate
gland will not grow to full size.
In some older men the prostate may continue
to grow, especially the part that is around the
urethra. This can make it more difficult for the
man to pass urine as the growing prostate
gland may be causing the urethra to collapse.
When the prostate gland becomes too big in
this way, the condition is called Benign
Prostatic Hyperplasia (BPH). BPH is not
cancer, but must be treated.
Prostate Cancer
In the vast majority of cases, the prostate
cancer starts in the gland cells - this is called
adenocarcinoma. In this article, prostate
cancer refers just to adenocarcinoma.
Prostate cancer is mostly a very slow
progressing disease. In fact, many men die of
old age, without ever knowing they had
prostate cancer - it is only when an autopsy is
done that doctors know it was there. Several
studies have indicated that perhaps about
80% of all men in their eighties had prostate
cancer when they died, but nobody knew, not
even the doctor.
Experts say that prostate cancer starts with
tiny alterations in the shape and size of the
prostate gland cells - Prostatic intraepithelial
neoplasia (PIN).
Doctors say that nearly 50% of all 50-year-old
men have PIN. The cells are still in place -
they do not seem to have moved elsewhere -
but the changes can be seen under a
microscope. Cancer cells would have moved
into other parts of the prostate. Doctors
describe these prostate gland cell changes as
low-grade or high-grade; high grade is
abnormal while low-grade is more-or-less
normal.
Any patient who was found to have high-grade
PIN after a prostate biopsy is at a
significantly greater risk of having cancer cells
in his prostate. Because of this, doctors will
monitor him carefully and possibly carry out
another biopsy later on.
Classification of prostate cancer
It is important to know the stage of the
cancer, or how far it has spread. Knowing the
cancer stage helps the doctor define prognosis
- it also helps when selecting which therapies
to use. The most common system today for
determining this is the TNM (Tumor/Nodes/
Metastases). This involves defining the size of
the tumor, how many lymph nodes are
involved, and whether there are any other
metastases.
When defining with the TNM system, it is
crucial to distinguish between cancers that
are still restricted just to the prostate, and
those that have spread elsewhere. Clinical T1
and T2 cancers are found only in the prostate,
and nowhere else, while T3 and T4 have
spread outside the prostate.
There are many ways to find out whether the
cancer has spread. Computer tomography will
check for spread inside the pelvis, bone scans
will decide whether the cancer has spread to
the bones, and endorectal coil magnetic
resonance imaging will evaluate the prostatic
capsule and the seminal vesicles.
The Gleason Score
A pathologist will look at the biopsy samples
under a microscope. If cancer tissue is
detected, the pathologist then grades the
tumor. The Gleason System of grading goes
from 2 to 10. The higher the number, the more
abnormal the tissues are compared to normal
prostate tissue.
Two numbers are added up to get a Gleason
score:
1. A number from 1 to 5 for the most
common pattern observed under the
microscope. This is the predominant grade
and must be more than 51% of the sample.
2. A number from 1 to 5 for the second most
common pattern. This is the secondary grade
and must make up more than 5% but less
than 50% of the sample.
A Gleason score of 7 can have two meanings.
Look at these two examples below:
1. If the predominant grade is 3 and the
secondary grade is 4, the Gleason score is 7.
2. If the predominant grade is 4 and the
secondary grade is 3, the Gleason score is
also 7.
However, the first example, with a
predominant score of 3, has a less aggressive
cancer than the second example, with a
predominant score of 4.
It is crucial that the tumor is graded properly,
as this decides what treatments should be
recommended.
What are the symptoms of prostate cancer ?
During the early stages of prostate cancer
there are usually no symptoms. Most men at
this stage find out they have prostate cancer
after a routine check up or blood test. When
symptoms do exist, they are usually one or
more of the following:
The patient urinates more often
The patient gets up at night more often to
urinate
He may find it hard to start urinating
He may find it hard to keep urinating once he
has started
There may be blood in the urine
Urination might be painful
Ejaculation may be painful (less common)
Achieving or maintaining an erection may be
difficult (less common)
If the prostate cancer is advanced the
following symptoms are also possible :
Bone pain, often in the spine (vertebrae),
pelvis, or ribs
The proximal part of the femur can be painful
Leg weakness (if cancer has spread to the
spine and compressed the spinal cord)
Urinary incontinence (if cancer has spread to
the spine and compressed the spinal cord)
Fecal incontinence (if cancer has spread to
the spine and compressed the spinal cord)
What are the causes of prostate cancer ?
Nobody is really sure of what the specific
causes are. There are so many possible
factors, including age, race, lifestyle,
medications, and genetics, to name a few.
Age
Age is considered as the primary risk factor.
The older a man is, the higher is his risk.
Prostate cancer is rare among men under the
age of 45, but much more common after the
age of 50.
Genetics
Statistics indicate that genetics is definitely a
factor in prostate cancer risk. It is more
common among certain racial groups - in the
USA prostate cancer is significantly more
common and also more deadly among Afro-
Americans than White-Americans. A man has
a much higher risk of developing cancer if his
identical twin has it. A man whose brother or
father had/had prostate cancer runs twice the
risk of developing it, compared to other men.
Studies indicate that the two faulty genes -
BRCA 1 and BRCA 2 - which are important
risk factors for breast cancer and ovarian
cancer, have also been implicated in prostate
cancer risk.
In a study scientists found seven new sites in
the human genome that are linked to men's
risk of developing prostate cancer.
Faulty BRCA2 gene linked to aggressive form
of prostate cancer - researchers at the The
Institute of Cancer Research, UK, reported in
the Journal of Clinical Oncology (April 2013
issue) that men who have inherited the faulty
BRCA2 gene are more likely to have the
faster-spreading type of prostate cancer . The
scientists say these men should receive
treatment immediately after diagnosis with
surgery or radiation therapy, rather than
receive the "watchful waiting" approach.
Senior author Ros Eeles wrote that experts
have already known that those with the faulty
BRCA2 gene have a higher risk of developing
prostate cancer. This is the first large study
to demonstrate that the faulty gene is also
linked to a faster spread of the disease and
poorer survival.
This new discovery will make some health
authorities around the world rethink their
policies and procedures. In the United
Kingdom, the National Health Service offers
the same prostate cancer treatment for both
carriers and non-carriers of the faulty BRCA2
gene.
Prof. Eeles said "It must make sense to start
offering affected men immediate surgery or
radiotherapy, even for early-stage cases that
would otherwise be classified as low-risk. We
won't be able to tell for certain that earlier
treatment can benefit men with inherited
cancer genes until we've tested it in a clinical
trial, but the hope is that our study will
ultimately save lives by directing treatment at
those who most need it."
Diet
A review of diets indicated that the
Mediterranean diet may reduce a person's
chances of developing prostate cancer .
Another study indicates that soy, selenium
and green tea, offer additional possibilities for
disease prevention - however, a more recent
study indicated that combination therapy of
vitamin E, selenium and soy does not prevent
the progression from high-grade prostatic
intraepithelial neoplasia (HGPIN) to prostate
cancer. A diet high in vegetable consumption
was found in a study to be beneficial.
A US pilot study on men with low risk
prostate cancer found that following an
intensive healthy diet and lifestyle regime
focusing on low meat and high vegetable and
fruit intake, regular exercise, yoga stretching,
meditation and support group participation,
can alter the way that genes behave and
change the progress of cancer, for instance by
switching on tumor killers and turning down
tumor promoters.
Other studies have indicated that lack of
vitamin D , a diet high in red meat may raise
a person's chances of developing prostate
cancer.
A study published in the journal Clinical
Cancer Research suggests vitamin D
deficiency may predict aggressive prostate
cancer .
Medication
Some studies say there might be a link
between the daily use of anti-inflammatory
medicines and prostate cancer risk. A study
found that statins, which are used to lower
cholesterol levels, may lower a person's risk
of developing prostate cancer.
Obesity
A study found a clear link between obesity
and raised prostate cancer risk, as well as a
higher risk of metastasis and death among
obese people who develop prostate cancer.
Sexually transmitted diseases (STDs)
Men who have had gonorrhea have a higher
chance of developing prostate cancer,
according to research from the University of
Michigan Health System .
Agent Orange
Veterans exposed to Agent Orange have a
48% higher risk of prostate cancer recurrence
following surgery than their unexposed peers,
and when the disease comes back, it seems
more aggressive, researchers say. Another
study found that Vietnam War veterans who
had been exposed to Agent Orange have
significantly increased risks of prostate
cancer and even greater risks of getting the
most aggressive form of the disease as
compared to those who were not exposed.
Enzyme PRSS3 linked to aggressive prostate
cancer
Scientists from the Mayo Clinic, Florida,
reported in Molecular Cancer Research that
PRSS3, an enzyme, changes the environment
of prostate cancer cells, making the cancer
much more likely to metastasize.
Senior researcher, Evette Radisky, Ph.D., said
"This molecule is a protease, which means it
digests other molecules. Our data suggests
PRSS3 activity changes the environment
around prostate cancer cells - perhaps by
freeing them from surrounding tissue - to
promote malignancy and invasiveness. I don't
think PRSS3 is the only factor involved in
driving aggressive prostate cancer, but it may
be significant for a certain subset of this
cancer - the kind that is potentially lethal."
Recent developments on prostate cancer
causes from MNT news
Chronic prostate inflammation tied to
nearly double risk of prostate cancer - a
study reported in the journal Cancer
Epidemiology, Biomarkers & Prevention,
finds that compared to men with no such
signs, men with chronic inflammation in
non-cancerous prostate tissue may have
nearly double the risk of developing
prostate cancer.
What are the treatments for prostate cancer?
Early stage prostate cancer
If the cancer is small and contained -
localized - it is usually managed by one of the
following treatments:
Watchful waiting - not immediate treatment is
carried out. PSA blood levels are regularly
monitored.
Radical prostatectomy - the prostate is
surgically removed.
Brachytherapy - radioactive seeds are
implanted into the prostate.
Conformal radiotherapy - the radiation beams
are shaped so that the region where they
overlap is as close to the same shape as the
organ or region that requires treatment, thus
minimizing healthy tissue exposure to
radiation.
Intensity modulated radiotherapy - beams
with variable intensity are used. An advanced
form of conformal radiotherapy usually
delivered by a computer-controlled linear
accelerator.
Treatment recommendations really depend on
individual cases. In general, if there is a good
prognosis and the cancer is in its early
stages, all options can be considered.
However, they all have their advantages and
disadvantages. The patient should discuss
available options thoroughly with his doctor.
More advanced prostate cancer
If the cancer is more aggressive, or advanced,
the patient may require a combination of
radiotherapy and hormone therapy.
Radiotherapy requires treatment on an
everyday basis for up to about eight weeks.
Radical surgery is also an option - the
prostate is removed. Traditional surgery
requires a hospital stay of up to ten days,
with a recovery time that can last up to three
months. Robotic keyhole surgery has the
advantage just a couple of days in hospital,
followed by a much shorter recover period.
However, even robotic keyhole surgery may
not be ideal for very elderly patients.
In advanced prostate cancer hormone therapy
is very effective in slowing down, and even
stopping the growth of cancer cells. Even if
the hormone therapy stops working after a
while, there are still other options the patient
will be able to discuss with his doctor, such
as participating in clinical trials.
Radioactive injection helps advanced prostate
cancer patients live longer - scientists at The
Royal Marsden NHS Foundation Trust and
The Institute of Cancer Research, UK, reported
in NEJM (New England Journal of Medicine)
that radium-233 , a radiation injection,
directly targets tumors in the bone delivering
short range radiation, causing minimal
damage to healthy tissue. Radium, like
calcium , is absorbed by the bone.
Dr Chris Parker and colleagues found that
late-stage prostate cancer patients who were
given the radioactive injection lived for an
average of 15 weeks longer than those given
an inert placebo injection.
Dr Parker said "We're excited by the prospects
for this ingenious new treatment, which takes
advantage of the properties of tumors
growing within bone to home in and deliver a
highly targeted dose of radiation. We were
delighted to show that radium 223 allowed
many men in our trial to live to see a few
extra, precious months. Not only did they live
longer, these men had a much better quality
of life."
Delivering estrogen through skin patches may
be an easier and safer way to treat prostate
cancer than the hormone therapies that are
currently used , British researchers explained
in Lancet Oncology (March 2013 issue).
In May 2013, the US FDA approved Xofigo
(radium Ra 223 dichloride) for metastatic
castration-resistant prostate cancer that has
reached bones but not other organs.
Enzalutamide is taken in combination with
docetaxel, another cancer medication.
Richard Pazdur, M.D., from the FDA, said
"Xofigo binds with minerals in the bone to
deliver radiation directly to bone tumors,
limiting the damage to the surrounding
normal tissues. Xofigo is the second prostate
cancer drug approved by the FDA in the past
year that demonstrates an ability to extend
the survival of men with metastatic prostate
cancer."
Xtandi (enzalutamide) was approved by the
FDA in August 2012 for patients with
metastatic castration-resistant prostate
cancer that has spread or recurred.
The problem with the Internet for many
prostate cancer patients
Researchers from Loyola University Medical
Center reported in the Journal of Urology that
one third of American lay people find it hard
to understand most information websites
regarding prostate cancer . Senior author,
Gopal Gupta, MD, said: "This is problematic
for one-third of Americans who seek to further
educate themselves using online resources."
Coffee and prostate cancer
Heavy coffee drinking may prevent cancer
recurrence or progression - men with prostate
cancer who consume at least four cups of
coffee per day may have a lower risk of
disease progression or recurrence, researchers
from the Fred Hutchinson Cancer Research
Center reported in the journal Cancer Causes
and Control.
What are the possible complications of
prostate cancer ?
Metastasis - the cancer can spread to other
parts of the body through the bloodstream or
the lymphatic system to other organs or
bones. If the cancer spreads to the ureters,
the tubes that carry urine from the kidneys to
the bladder, there is a risk of serious kidney
problems.
If the cancer spreads to the bones, there may
be pain and fractures. Doctors say that when
prostate cancer has spread to other parts of
the body, it can no longer be cured, but may
possibly be controlled.
Incontinence - the prostate cancer itself, or
treatments can cause urinary incontinence.
Erectile dysfunction - the prostate cancer or
prostate cancer treatment can lead to erectile
dysfunction - the inability to achieve a penile
erection, or maintain one.
Metabolic factors - a man's risk of dying from
prostate cancer is much higher if he has high
blood pressure, raised blood sugar levels,
high blood lipid levels, and a high BMI (body
mass index), which collectively are known as
metabolic factors. This was reported in the
journal Cancer (October 2012 issue) by
scientists from Umeå University in Sweden.
Fertility advice crucial for male cancer
survivors
Researchers at the University of Sheffield, UK,
found that the majority of male cancer
patients are not receiving vital fertility advice.
Males with cancer who are at risk of long-
term infertility should be advised on the
advantages and benefits of sperm banking.
Cancer treatments, such as radiotherapy and
chemotherapy, can seriously affect a cancer
patient's long term fertility, head researcher Dr
Allan Pacey explained.
Dr Pacey said: "Trying to engage men with
this subject is notoriously difficult. For those
of us who run sperm banks, many men store
their sperm and then do not contact us again,
even though there are legal reasons to keep in
contact. Our research suggests that there is a
need to educate men about the benefits of
attending follow-up fertility clinics and the
long-term consequences of non-attendance."
Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without the permission
of Medical News Today.
No comments:
Post a Comment