Back to Oncology Diseases
and edited by: Dr. Safaa
Mahmoud, M.D. Lecturer of Clinical Oncology.
Cairo University, Egypt.
Saturday 18th October, 2008.
Prostate cancer is the most common type of cancer in men in the
United States other than skin cancer. Of all the men who are diagnosed
with cancer each year, more than one-fourth have prostate cancer.
Research is increasing our understanding of prostate cancer.
Scientists are learning more about the possible causes of prostate
cancer and are looking for new ways to prevent, detect, diagnose, and
treat this disease. Because of this research, men with prostate cancer
now have a lower chance of dying from the disease.
The normal prostate
The prostate is a gland in a man's reproductive system. It makes
and stores seminal fluid, a milky fluid that nourishes sperm. This
fluid is released to form part of semen. The prostate is about the
size of a walnut. It is located below the bladder and in front of the
rectum. It surrounds the upper part of the urethra, the tube that
empties urine from the bladder. If the prostate grows too large, the
flow of urine can be slowed or stopped. To work properly, the prostate
needs male hormones (androgens). Male hormones are responsible for
male sex characteristics. The main male hormone is testosterone, which
is made mainly by the testicles. Some male hormones are produced in
small amounts by the adrenal glands.
Understanding the cancer process
Cancer is a group of many related diseases. These diseases begin in
cells, the body's basic unit of life. Cells have many important
functions throughout the body. Normally, cells grow and divide to form
new cells in an orderly way. They perform their functions for a while,
and then they die. This process helps keep the body healthy.
Sometimes, however, cells do not die. Instead, they keep dividing and
creating new cells that the body does not need. They form a mass of
tissue, called a growth or tumor.
Tumors of the prostate
Tumors can be benign or malignant: Benign tumors are not cancer.
They can usually be removed, and in most cases, they do not come back.
Cells from benign tumors do not spread to other parts of the body.
Most important, benign tumors of the prostate are not a threat to
life. Benign prostatic hyperplasia (BPH) is the abnormal growth of
benign prostate cells. In BPH, the prostate grows larger and presses
against the urethra and bladder, interfering with the normal flow of
urine. More than half of the men in the United States between the ages
of 60 and 70 and as many as 90 percent between the ages of 70 and 90
have symptoms of BPH. For some men, the symptoms may be severe enough
to require treatment.
Malignant tumors are cancer. Cells in these tumors are abnormal.
They divide without control or order, and they do not die. They can
invade and damage nearby tissues and organs. Also, cancer cells can
break away from a malignant tumor and enter the bloodstream and
lymphatic system. This is how cancer spreads from the original
(primary) cancer site to form new (secondary) tumors in other organs.
The spread of cancer is called metastasis.
When prostate cancer spreads (metastasizes) outside the prostate,
cancer cells are often found in nearby lymph nodes. If the cancer has
reached these nodes, it means that cancer cells may have spread to
other parts of the body -- other lymph nodes and other organs, such as
the bones, bladder, or rectum. When cancer spreads from its original
location to another part of the body, the new tumor has the same kind
of abnormal cells and the same name as the primary tumor. For example,
if prostate cancer spreads to the bones, the cancer cells in the new
tumor are prostate cancer cells. The disease is metastatic prostate
cancer; it is not bone cancer.
Are you a doctor or a nurse?
Do you want to join the Doctors Lounge online medical community?
Participate in editorial activities (publish, peer review, edit) and
give a helping hand to the largest online community of patients.
Click on the link below to see the requirements:
Doctors Lounge Membership
Risk factors for prostate cancer
The causes of prostate cancer are not well understood. Doctors
cannot explain why one man gets prostate cancer and another does not.
Researchers are studying factors that may increase the risk of this
disease. Studies have found that the following risk factors are
associated with prostate cancer:
- Age. In the United States, prostate cancer is found mainly in
men over age 55. The average age of patients at the time of
diagnosis is 70.
- Family history of prostate cancer. A man's risk for developing
prostate cancer is higher if his father or brother has had the
- Race. This disease is much more common in African American men
than in white men. It is less common in Asian and American Indian
- Diet and dietary factors. Some evidence suggests that a diet
high in animal fat may increase the risk of prostate cancer and a
diet high in fruits and vegetables may decrease the risk. Studies
are in progress to learn whether men can reduce their risk of
prostate cancer by taking certain dietary supplements.
- High testosterone levels. Testosterone hormone stimulates the
growth of the prostate gland. Many studies proved that long term
testosterone therapy and high testosterone blood level may cause
prostate gland enlargement (benign prostatic hyperplasia) and may
increase the risk f developing cancer prostate.
- Although a few studies suggested that having a vasectomy might
increase a man's risk for prostate cancer, most studies do not
support this finding. Scientists have studied whether benign
prostatic hyperplasia, obesity, lack of exercise, smoking, radiation
exposure, or a sexually transmitted virus might increase the risk
for prostate cancer. At this time, there is little evidence that
these factors contribute to an increased risk.
Screening for prostate cancer
A man who has any of the risk factors may want to ask a doctor
whether to begin screening for prostate cancer (even though he does
not have any symptoms), what tests to have, and how often to have
them. The doctor may suggest either of the tests described below.
These tests are used to detect prostate abnormalities, but they cannot
show whether abnormalities are cancer or another, less serious
condition. The doctor will take the results into account in deciding
whether to check the patient further for signs of cancer. The doctor
can explain more about each test. Digital rectal examination: The doctor inserts a lubricated, gloved
finger into the rectum and feels the prostate through the rectal wall
to check for hard or lumpy areas.
According to the American Cancer Society (ACS) and the American Urological
Association (AUA) recommendations for the early detection of prostate cancer are
an annual digital rectal examination (DRE) and serum PSA test beginning at age
50 in the absence of specific risk factors and earlier for those in high-risk
- Blood test for prostate-specific antigen (PSA): A lab measures the
levels of PSA in a blood sample. The level of PSA may rise in men who
have prostate cancer, BPH, or infection in the prostate. The traditional PSA level at which biopsy is recommended was
4.0 ng/mL, now many
physicians consider recommending a biopsy at a PSA level in the range of
2.5 to 4.0 ng/mL.
- PSA derivatives:
- Percent-free PSA: PSA exists in the body in different forms either free or bound
to other proteins. The percentage of the free PSA level to the total PSA is what
we call Percent-free PSA. This is an alternative test used when the total PSA
levels between 4-10 ng/mL and a biopsy can not be done. A value of ≤25% means a
biopsy is recommended and the probability of having cancer is high.
- PSA Velocity:
The rate of change in PSA over time is called the PSA velocity (PSAV). A cutoff
of 0.75 ng/mL/year raises the suspicion of cancer when PSA levels were between 4-10 ng/ml.
It is also important to know that there are opponents for routine early
detection programs since no available data from randomized trials proved the
advantage of early disease detection in terms of decreasing death rates from the disease. For
this reason, the US Preventive Services Task Force and the American College of
Physicians do not recommend performing routine PSA evaluation for prostate
However, all agree that screening programs have allowed the early
localized cancer and markedly decreased the frequency of metastatic disease at diagnosis.
Symptoms of Prostate cancer
Early prostate cancer often does not cause symptoms. But prostate
cancer can cause any of these problems:
- A need to urinate frequently, especially at night;
- Difficulty starting urination or holding back urine;
- Inability to urinate;
- Weak or interrupted flow of urine;
- Painful or burning urination;
- Difficulty in having an erection;
- Painful ejaculation;
- Blood in urine or semen; or
- Frequent pain or stiffness in the lower back, hips, or upper
Any of these symptoms may be caused by cancer or by other, less
serious health problems, such as BPH or an infection. A man who has
symptoms like these should see his doctor or a urologist (a doctor who
specializes in treating diseases of the genitourinary system).
Diagnosis of prostate cancer
If a man has symptoms or test results that suggest prostate cancer,
his doctor asks about his personal and family medical history,
performs a physical exam, and may order laboratory tests. The exams
and tests may include a digital rectal exam, a urine test to check for
blood or infection, and a blood test to measure PSA. In some cases,
the doctor also may check the level of prostatic acid phosphatase
(PAP) in the blood and PSA derivatives, especially if the results of the PSA indicate
there might be a problem. The doctor may order exams to learn more
about the cause of the symptoms. These may include:
- Transrectal ultrasonography -- sound waves that cannot be heard
by humans (ultrasound) are sent out by a probe inserted into the
rectum. The waves bounce off the prostate, and a computer uses the
echoes to create a picture called a sonogram.
- Intravenous pyelogram -- a series of x-rays of the organs of the
If test results suggest that cancer may be present, the man will
need to have a biopsy. During a biopsy, the doctor removes tissue
samples from the prostate, usually with a needle. A pathologist looks
at the tissue under a microscope to check for cancer cells. If cancer
is present, the pathologist usually reports the grade of the tumor.
The grade tells how much the tumor tissue differs from normal prostate
tissue and suggests how fast the tumor is likely to grow. One way of
grading prostate cancer, called the Gleason system, uses scores of 2
to 10. Another system uses G1 through G4. Tumors with higher scores or
grades are more likely to grow and spread than tumors with lower
If the physical exam and test results do not suggest cancer, the
doctor may recommend medicine to reduce the symptoms caused by an
enlarged prostate. Surgery is another way to relieve these symptoms.
The surgery most often used in such cases is called transurethral
resection of the prostate (TURP or TUR). In TURP, an instrument is
inserted through the urethra to remove prostate tissue that is
pressing against the upper part of the urethra and restricting the
flow of urine. (Patients may want to ask whether other procedures
might be appropriate).
Stages of prostate cancer
If cancer is found in the prostate, the doctor needs to know the
stage, or extent, of the disease. Staging is a careful attempt to find
out whether the cancer has spread and, if so, what parts of the body
are affected. The doctor may use various blood and imaging tests to
learn the stage of the disease. Treatment decisions depend on these
Prostate cancer staging is a complex process. The doctor may
describe the stage using a Roman number (I-IV) or a capital letter
Treatment for prostate cancer
Treatment for prostate cancer may involve watchful waiting,
surgery, radiation therapy, or hormonal therapy. Some patients receive
a combination of therapies. In addition, doctors are studying other
methods of treatment to find out whether they are effective against
Watchful waiting also known as deferred treatment or active
surveillance is decided based on estimation of the patient life
expectancy, complete staging, comorbidities and the reliability of
close follow up and monitoring. A lot of work is being done to
better define the criteria for selecting patients who would benefit
the most from this approach without negatively affecting their
Watchful waiting may be suggested for some men who have prostate
cancer that is found at an early stage and appears to be slow growing.
Also, watchful waiting may be advised for older men or men with other
serious medical problems. For these men, the risks and possible side
effects of surgery, radiation therapy, or hormonal therapy may
outweigh the possible benefits. Men with early stage prostate cancer
are taking part in a study to determine when or whether treatment may
be necessary and effective.
Although men who choose watchful waiting avoid the side effects of
surgery and radiation, there can be some negative aspects to this
choice. Watchful waiting may reduce the chance of controlling the
disease before it spreads. Also, older men should keep in mind that it
may be harder to manage surgery and radiation therapy as they age.
Some men may decide against watchful waiting because they feel they
would be uncomfortable living with an untreated cancer, even one that
appears to be growing slowly or not at all. A man who chooses watchful
waiting but later becomes concerned or anxious should discuss his
feelings with his doctor. A different treatment approach is nearly
Surgery is a common treatment for early stage prostate cancer. The
doctor may remove the entire prostate (a type of surgery called
radical prostatectomy) or only part of it. In some cases, the doctor
can use a new technique known as nerve-sparing surgery. This type of
surgery may save the nerves that control erection. However, men with
large tumors or tumors that are very close to the nerves may not be
able to have this surgery.
The doctor can describe the types of surgery and can discuss and
compare their benefits and risks. In radical retropubic prostatectomy,
the doctor removes the entire prostate and nearby lymph nodes through
an incision in the abdomen.
In radical perineal prostatectomy, the doctor removes the entire
prostate through an incision between the scrotum and the anus. Nearby
lymph nodes are sometimes removed through a separate incision in the
In transurethral resection of the prostate (TURP), the doctor
removes part of the prostate with an instrument that is inserted
through the urethra. The cancer is cut from the prostate by
electricity passing through a small wire loop on the end of the
instrument. This method is used mainly to remove tissue that blocks
Laparoscopic and Robot-assisted radical prostatectomy are
commonly used now. They give comparable results to traditional
surgery in experienced centers and with less blood loss.
Whether to remove lymph nodes during radical prostatectomy or not
is now evaluated using especial tables or special computer programs
(nomograms) that tell the possible risk of having lymph node
metastases that warrants their removal.
If the pathologist finds cancer cells in the lymph nodes, it is
likely that the disease has spread to other parts of the body.
Sometimes, the doctor removes the lymph nodes before doing a
prostatectomy. If the prostate cancer has not spread to the lymph
nodes, the doctor then removes the prostate. But if cancer has spread
to the nodes, the doctor usually does not remove the prostate, but may
suggest other treatment.
Patients are often uncomfortable for the first few days after
surgery. Their pain usually can be controlled with medicine, and
patients should discuss pain relief with the doctor or nurse. The
patient will wear a catheter (a tube inserted into the urethra) to
drain urine for 10 days to 3 weeks. The nurse or doctor will show the
man how to care for the catheter.
It is also common for patients to feel extremely tired or weak for
a while. The length of time it takes to recover from an operation
varies. Surgery to remove the prostate may cause long-term problems,
including rectal injury or urinary incontinence. Some men may have
permanent impotence. Nerve-sparing surgery is an attempt to avoid the
problem of impotence. When the doctor can use nerve-sparing surgery
and the operation is fully successful, impotence may be only
temporary. Still, some men who have this procedure may be permanently
Men who have a prostatectomy no longer produce semen, so they have
dry orgasms. Men who wish to father children may consider sperm
banking or a sperm retrieval procedure.
Radiation therapy (also called radiotherapy) uses high-energy
x-rays to kill cancer cells. Like surgery, radiation therapy is local
therapy; it can affect cancer cells only in the treated area. In early
stage prostate cancer, radiation can be used instead of surgery, or it
may be used after surgery to destroy any cancer cells that may remain
in the area. In advanced stages, it may be given to relieve pain or
Radiation may be directed at the body by a linear accelerator, or
it may come from tiny radioactive seeds placed inside or near the
tumor (internal or implant radiation, or brachytherapy). Men who
receive radioactive seeds alone usually have very small tumors
confined to the prostate. Some men
with prostate cancer receive both kinds of radiation therapy.
Improvement of the local control using radiation therapy was an
area of active research. Passing from the standard two dimensional
2D radiation therapy technique through the three dimensional 3D
conformal radiation therapy (3DCRT) that uses computer systems to
the most recent techniques, the intensity modulated system. These
advances allowed the delivery of higher radiation doses to cancer
cells with less exposure of the normal surrounding tissues and
organs to radiation therapy.
Radiation doses differ according to the patient risk group (his
stage, PSA, and Gleason score). As for surgery, whether to treat
pelvic lymph nodes or not depends on patient risk categorization,
only low risk patients do not receive pelvic radiation therapy.
For external radiation therapy, patients go to the hospital or
clinic, usually 5 days a week for several weeks. Patients may stay in
the hospital for a short time for implant radiation.
Radiation therapy may cause patients to become extremely tired,
especially in the later weeks of treatment. Resting is important, but
doctors usually encourage men to try to stay as active as they can.
Some men may have diarrhea or frequent and uncomfortable urination.
When men with prostate cancer receive external radiation therapy,
it is uncommon for the skin in the treated area to become red, dry, or
tender, however there may be hair loss in the treated area. The loss
is usually temporary.
Both types of radiation therapy may cause impotence in some men.
While internal radiation therapy may cause temporary urinary
incontinence, external radiation therapy causes temporary bowel
inflammation. Long-term side effects from internal radiation therapy
Hormonal therapy keeps cancer cells from getting the male hormones
they need to grow. It is called systemic therapy because it can
affect cancer cells throughout the body. Systemic therapy is used to
treat cancer that has spread. Sometimes this type of therapy is used
to try to prevent the cancer from coming back after surgery or
radiation treatment in patients considered at high risk for
There are several forms of hormonal therapy:
- Orchiectomy is surgery to remove the testicles, which are the main
source of male hormones.
- Drugs known as luteinizing hormone-releasing hormone (LH-RH) agonists
can prevent the testicles from producing testosterone. Examples are
leuprolide, goserelin, and buserelin.
- Drugs known as antiandrogens can block the action of androgens. Two
examples are flutamide and bicalutamide.
- Drugs that can prevent the adrenal glands from making androgens
include ketoconazole and aminoglutethimide.
After orchiectomy or treatment with an LH-RH agonist, the body no
longer gets testosterone from the testicles. However, the adrenal
glands still produce small amounts of male hormones. Sometimes, the
patient is also given an antiandrogen, which blocks the effect of any
remaining male hormones. This combination of treatments is known as
total androgen blockade (TAB), combined hormonal therapy (CHT),
combined androgen blockade (CAB), or maximal androgen deprivation
(MAD). Studies have not shown a superior efficacy for combined
hormonal blockade over castration alone. Doctors may use combined
hormonal blockade only during the initial 7 days of radiation
therapy to bone aiming to avoid flare of symptoms, a known side
effect during the initiation of an LH-RH agonist treatment (as
Prostate cancer that has spread to other parts of the body usually
can be controlled with hormonal therapy for a period of time, often
several years. Eventually, however, most prostate cancers are able to
grow with very little or no male hormones (hormone refractory). When this happens, hormonal
therapy is no longer effective, and the doctor may suggest other forms
of treatment that are under study.
The side effects of hormonal therapy depend largely on the type of
treatment. Orchiectomy and LH-RH agonists often cause side effects
such as impotence, hot flashes, and loss of sexual desire. When first
taken, an LH-RH agonist may make a patient's symptoms worse for a
short time. This temporary problem is called "flare." Gradually,
however, the treatment causes a man's testosterone level to fall.
Without testosterone, tumor growth slows down and the patient's
condition improves. (To prevent flare, the doctor may give the man an
antiandrogen for a while along with the LH-RH agonist.)
Antiandrogens can cause nausea, vomiting, diarrhea, or breast
growth or tenderness. If used a long time, ketoconazole may cause
liver problems, and aminoglutethimide can cause skin rashes. Men who
receive total androgen blockade may experience more side effects than
men who receive a single method of hormonal therapy. Any method of
hormonal therapy that lowers androgen levels can contribute to
weakening of the bones in older men.
Treatment for those who have disseminated disease and are hormone
refractory is chemotherapy. The currently approved drugs are
Docetaxel, Novantrone, and Estramustine and more recently
Follow up care
During and after treatment, the doctor will continue to follow the
patient. The doctor will examine the man regularly to be sure that the
disease has not returned or progressed, and will decide what other
medical care may be needed. Follow up exams may include x-rays, scans,
and lab tests, such as the PSA blood test.