What
is the prostate?
The prostate is a gland in the male reproductive system. The
prostate makes and stores a component of semen and is located
near the bladder and the rectum. The prostate surrounds part
of the urethra, the tube that empties urine from the bladder.
A healthy prostate is about the size of a walnut. If the prostate
grows too large, the flow of urine can be slowed or stopped.
What is prostate cancer?
Except for skin cancer, cancer of the prostate is the most
common malignancy in American men. It is estimated that nearly
221,000 men in the United States will be diagnosed with prostate
cancer in 2003. In most men with prostate cancer, the disease
grows very slowly. The majority of men with low-grade, early
prostate cancer (confined to the gland) live
a long time after their diagnosis. Even without treatment,
many of these men will not die of the prostate cancer,
but rather will live with it until they eventually die of
some other, unrelated cause. Nevertheless, nearly 29,000 men
will die of prostate cancer in 2003.
Who is at risk for prostate cancer?
All men are at risk. The most common risk factor is age. More
than 70 percent of men diagnosed with prostate cancer
each year are over the age of 65. African American men have
a higher risk of prostate cancer than white men. Dramatic
differences in the incidence of prostate cancer are also seen
in different countries, and there is some evidence that a
diet higher in fat, especially animal fat, may account for
some of these differences. Genetic factors also appear to
play a role, particularly for families in whom the diagnosis
is made in men under 60 years of age. The risk of prostate
cancer rises with the number of close relatives who
have the disease.
What are the symptoms of prostate cancer?
Prostate cancer often does not cause symptoms for many years.
By the time symptoms occur, the disease may have spread beyond
the prostate. When symptoms do occur, they may include:
•
Frequent urination, especially at night
•
Inability to urinate
•
Trouble starting or holding back urination
•
A weak or interrupted flow of urine
•
Painful or burning urination
•
Blood in the urine or semen
•
Painful ejaculation
•
Frequent pain in the lower back, hips, or upper thighs
These
can be symptoms of cancer, but more often they are symptoms
of noncancerous conditions. It is important to check with
a doctor.
What other prostate conditions can cause symptoms
like these?
As men get older, their prostate may grow bigger and block
the flow of urine or interfere with sexual function. This
common condition, called benign prostatic hyperplasia (BPH),
is not cancer, but can cause many of the same symptoms as
prostate cancer. Although BPH may not be a threat to life,
it may require treatment with medicine or surgery to relieve
symptoms. An infection or inflammation of the prostate, called
prostatitis, may also cause many of the same symptoms as prostate
cancer. Again, it is important to check with a doctor.
Can prostate cancer be found before a man has symptoms?
Yes. Two tests can be used to detect prostate cancer
in the absence of any symptoms. One is the digital rectal
exam (DRE), in which a doctor feels the prostate through the
rectum to find hard or lumpy areas. The other is a blood test
used to detect a substance made by the prostate called prostate
specific antigen (PSA). Together, these tests can detect many
“silent” prostate cancers, those that have not
caused symptoms.
At present, however, it is not known whether routine screening
saves lives. The benefits of screening and local therapy (surgery
or radiation) remain unclear for many patients. Because of
this uncertainty, the National Cancer Institute is currently
supporting research to learn more about screening men for
prostate cancer. Currently, researchers are conducting a large
study to determine whether screening men using a blood test
for PSA and a DRE can help reduce the death rate from this
disease. They are also assessing the risks of screening. Full
results from this study, the Prostate, Lung, Colorectal, and
Ovarian Cancer Screening Trial or PLCO, are expected by 2015.
How reliable are the screening tests for prostate cancer?
Neither of the screening tests for prostate cancer
is perfect. Most men with mildly elevated PSA levels do not
have prostate cancer, and many men with prostate cancer have
normal levels of PSA. Also, the DRE can miss many prostate
cancers. The DRE and PSA test together are better than either
test alone in detecting prostate cancer.
How is prostate cancer diagnosed?
The diagnosis of prostate cancer can be confirmed
only by a biopsy. During a biopsy, a urologist (a doctor who
specializes in diseases of urinary and sex organs in men,
and urinary organs in women) removes tissue samples, usually
with a needle. This is generally done in the doctor’s
office with local anesthesia. Then a pathologist (a doctor
who identifies diseases by studying tissues under a microscope)
checks for cancer cells.
Prostate cancer is described by both grade and stage.
Grade
describes how closely the tumor resembles normal prostate
tissue. Based on the microscopic appearance of tumor tissue,
pathologists may describe it as low-, medium-, or high-grade
cancer. One way of grading prostate cancer, called the Gleason
system, uses scores of 2 to 10. Another system uses G1 through
G4. In both systems, the higher the score, the higher the
grade of the tumor. High-grade tumors generally grow more
quickly and are more likely to spread than low-grade tumors.
Stage
refers to the extent of the cancer. Early prostate cancer,
stages I and II, is localized. It has not spread outside the
gland. Stage III prostate cancer, often called
locally advanced disease, extends outside the gland to the
seminal vesicles. Stage IV means the cancer has spread to
lymph nodes and/or to other tissues or organs.
How
is localized prostate cancer treated?
Three treatment options are generally accepted for men with
localized prostate cancer: radical prostatectomy, radiation
therapy, and surveillance (also called watchful waiting).
Radical
prostatectomy is a surgical procedure to remove the entire
prostate gland and nearby tissues. Sometimes lymph nodes in
the pelvic area (the lower part of the abdomen, located between
the hip bones) are also removed. Radical prostatectomy may
be performed using a technique called nerve-sparing surgery
that may prevent damage to the nerves needed for an erection.
Radiation
therapy involves the delivery of radiation energy to the prostate.
The energy is usually delivered in an outpatient setting using
an external beam of radiation. The energy can also be delivered
by implanting radioactive seeds in the prostate using a needle.
Surveillance,
taking a wait-and-see approach, may be recommended for patients
with early-stage prostate cancer, particularly those who are
older or have other serious medical conditions. These patients
have regular examinations. If there is evidence of cancer
growth, active treatment may be recommended.
How
does a patient decide what is the best treatment option for
localized prostate cancer?
Choosing a treatment option involves the patient, his family,
and one or more doctors. They will need to consider the grade
and stage of the cancer, the man’s age and health, and
his values and feelings about the potential benefits and harms
of each treatment option. Often it is useful to seek a second
opinion, and patients may hear different opinions and recommendations.
Because there are several reasonable options for most patients,
the decision can be difficult. Patients should try to get
as much information as possible and allow themselves enough
time to make a decision. There is rarely a need to make a
decision without taking time to discuss and understand the
pros and cons of the various approaches.
| http://cis.nci.nih.gov/fact/5_23.htm
| cancer.gov
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