- 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 in the pelvis,
under the bladder
and in front of 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. Because of the prostate’s location, the flow of
urine can be slowed or stopped if the prostate grows too
large.
- What is prostate cancer?
Prostate cancer forms in the tissues
of the prostate. Except for skin
cancer, cancer of the prostate is the most common malignancy
in American men. It is estimated that 218,890 men in the
United States will be diagnosed with prostate cancer in 2007 (1).
In most men with prostate cancer, the disease grows very
slowly. The majority of men with low-grade, early prostate
cancer (which means that cancer cells have been found only in
the prostate 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,
it is estimated that nearly 27,000 men will die from prostate
cancer in 2007 (1).
- Who is at risk for prostate
cancer?
An important risk factor is age; more than 70 percent of
men diagnosed with this disease are over the age of 65.
African American men have a substantially higher risk of
prostate cancer than white men, including Hispanic men.
Dramatic differences in the incidence
of prostate cancer are also seen in different populations
around the world. There is some evidence that dietary factors
are involved, such as vitamin
E and selenium,
which may have a protective effect. Genetic
factors also appear to play a role, particularly for families
in which the diagnosis is made in men under age 60. 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:
- Urinary
problems:
- Not being able to urinate.
- Having a hard time starting or stopping the urine
flow.
- Needing to urinate often, especially at night.
- Weak flow of urine.
- Urine flow that starts and stops.
- Pain or burning during urination.
- Difficulty having an erection.
- Blood
in the urine or semen.
- 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 that have not
caused symptoms. Due to the widespread implementation of PSA
testing in the United States, approximately 90 percent of all
prostate cancers are currently diagnosed at an early stage,
and, consequently, men are surviving longer after diagnosis.
At present, however, it is not known whether routine
prostate screening
saves lives. Screening is a term used to describe tests when
they are done in individuals who are not experiencing any
symptoms. The benefits of screening and local
therapy (surgery or radiation) remain unclear for many
patients. Because of this uncertainty, the National
Cancer Institute (NCI), a part of the National
Institutes of Health, 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 (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.
A recent study examining the PSA histories of men enrolled
in the Baltimore Longitudinal Study of Aging (BLSA) suggests
that PSA velocity may be a better indicator of potentially
life-threatening cancer than PSA level. PSA velocity is the
rate at which serum
PSA levels change over time. The study found that men who had
a PSA velocity above 0.35 ng/ml
per year had a higher relative risk of dying from prostate
cancer than men who had a PSA velocity less than 0.35 ng/ml
per year (2). More studies are needed to
determine if PSA velocity more accurately detects potentially
life-threatening prostate cancer early.
The NCI Early Detection Research Network (EDRN) has a
Prostate Collaborative Group, which is applying a variety of
strategies to find better ways to detect prostate cancer
early. In addition, the NCI’s prostate cancer Specialized
Program of Research Excellence (SPORE) program is funding
projects to identify new biomarkers
to detect 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.
Men may have blood tests to see if the cancer has spread.
Some men also may need the following imaging
tests:
- Bone
scan: The doctor injects
a small amount of a radioactive
substance into a blood
vessel. It travels through the bloodstream and
collects in the bones. A machine called a scanner
detects and measures the radiation. The scanner makes
pictures of the bones on a computer screen or on film. The
pictures may show cancer that has spread to the bones.
- CT
scan: An x-ray
machine linked to a computer takes a series of detailed
pictures of areas inside the body. Doctors often use CT
scans to see the pelvis or abdomen
.
- MRI:
A strong magnet linked to a computer is used to
make detailed pictures of areas inside the body.
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 and may be
in the seminal
vesicles. Stage IV means the cancer has spread beyond
the seminal vesicles 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 (with or without hormonal
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. However, nerve-sparing surgery is not
always possible.
- 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 in a technique known as brachytherapy,
which involves implanting radioactive seeds in the
prostate using a needle. Patients with high-risk prostate
cancer are candidates for adding hormonal therapy to
standard radiation therapy.
- Active Surveillance (watchful waiting) may
be an option recommended for patients with early-stage
prostate cancer, particularly those who have low-grade
tumors with only a small amount of cancer seen in the biopsy
specimen. These patients have regular examinations,
PSA testing, and sometimes scheduled biopsies. If there is
evidence of cancer growth, active treatment may be
recommended. Older patients and those with serious medical
problems may also be good candidates for active
surveillance.
- 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
harm of each treatment option. Since both surgery and
radiation therapy are options for localized disease,
consultation with both a urologist and a radiation
oncologist is recommended. Often it is useful to seek
additional opinions—from the same type of doctor, an
internist, a family practice physician,
or a medical
oncologist. Because there are several reasonable options
for most patients, patients may hear different opinions and
recommendations and the decision can be difficult. However,
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.
- Where can a person find more
information about prostate cancer and its treatment?
The NCI has several other resources that readers may find
helpful, including the following:
- The Prostate Cancer home page provides links to
NCI resources about prevention,
screening, treatment, clinical
trials, and supportive
care for this type of cancer. This page can be found
on the NCI’s Web site at http://www.cancer.gov/cancertopics/types/prostate
on the Internet.
- Prostate Cancer (PDQ®):
Treatment includes information about prostate cancer
treatment, including surgery, chemotherapy,
radiation therapy, and hormone
therapy. This summary of information from PDQ, the
NCI’s comprehensive cancer information database, is
available at http://www.cancer.gov/cancertopics/pdq/treatment/prostate/patient/
on the Internet.
- Treatment Choices for Men With Early-Stage Prostate
Cancer describes the treatment choices available to
men diagnosed with early-stage prostate cancer and
examines the pros and cons of each treatment. This NCI
fact sheet is available at http://www.cancer.gov/cancertopics/prostate-cancer-treatment-choices
on the Internet.