What is screening?
Cancer screening looks for a hidden cancer before a person has any warning signs or symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms. Screening tests may be repeated on a regular basis.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
Prostate cancer is a disease in which malignant (cancer) cells form in the tissues of the prostate.
The prostate is a gland in the male reproductive system located just below the bladder (the organ that collects and empties urine) and in front of the rectum (the lower part of the intestine). It is about the size of a walnut and surrounds part of the urethra (the tube that empties urine from the bladder). The prostate gland produces fluid that makes up part of semen.
As men age, the prostate may get bigger. A bigger prostate may block the flow of urine from the bladder and cause problems with urination. Rarely, this may cause problems with sexual function as well. This condition is called benign prostatic hyperplasia (BPH), and although it is not cancer, surgery may be needed to correct it. The symptoms of benign prostatic hyperplasia or of other problems in the prostate may be similar to symptoms of prostate cancer.
Normal prostate and benign prostatic hyperplasia (BPH). A normal prostate does not block the flow of urine from the bladder. An enlarged prostate presses on the bladder and urethra and blocks the flow of urine.
How common is prostate cancer?
Prostate cancer is the most common nonskin cancer among men in the United States.
Prostate cancer is found mainly in older men. Although the number of men with prostate cancer is large, most men diagnosed with this disease do not die from it. Prostate cancer occurs more often in African-American men than in white men. African-American men with prostate cancer are more likely to die from the disease than white men with prostate cancer.
What are prostate cancer risk factors?
Anything that increases a person's chance of developing a disease is called a risk factor. Risk factors for prostate cancer include the following:
What tests are used to screen for prostate cancer?
Some screening tests are used because they have been shown to be helpful both in finding cancers early and decreasing the chance of dying from these cancers. Other tests are used because they have been shown to find cancer in some people; however, it has not been proven in clinical trials that use of these tests will decrease the risk of dying from the cancer for which a person is being screened.
Scientists study screening tests to find those with the fewest risks and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) decreases a person's chance of dying from the disease. For some types of cancer, finding and treating the disease at an early stage may result in a better chance of recovery.
Screening tests used to detect prostate cancer.
Screening tests for prostate cancer continue to be under study. Decisions about undergoing screening for prosate cancer should be discussed one on one with a doctor. One may wish to participate in the study of screening tests for prostate cancer. These studies are called clinical trials. There are clinical trials taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site.
Tests to detect (find) prostate cancer that are being studied include the following:
Digital rectal exam
Digital rectal exam (DRE) is an exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel the prostate for lumps or anything else that seems unusual.
Digital rectal exam (DRE). The doctor inserts a gloved, lubricated finger into the rectum and feels the prostate to check for anything abnormal.
Prostate-specific antigen test
A prostate-specific antigen (PSA) test is a test that measures the level of PSA in the blood. PSA is a substance made mostly by the prostate that may be found in an increased amount in the blood of men who have prostate cancer. The level of PSA may also be high in men who have an infection or inflammation of the prostate or benign prostatic hyperplasia (BPH; an enlarged, but noncancerous, prostate).
Scientists are studying the combination of PSA testing and digital rectal exam as a way to get more accurate results from the screening tests.
What are the risks of prostate cancer screening tests?
Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
The risks of prostate screening include the following:
Finding prostate cancer may not improve health or help a man live longer.
Screening may not improve your health or help you live longer if you have cancer that has already spread to the area outside of the prostate or to other places in your body.
Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. Finding these cancers is called overdiagnosis. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer, such as surgery and radiation therapy, may have serious side effects.
Some studies of patients with prostate cancer showed these patients had a higher risk of death from cardiovascular (heart and blood vessel) disease or suicide. The risk was greatest the first year after diagnosis.
Follow-up tests, such as a biopsy, may be done to diagnose cancer.
If a PSA test is higher than normal, a biopsy of the prostate may be done. Complications from a biopsy of the prostate may include fever, pain, blood in the urine or semen, and urinary tract infection. Even if a biopsy shows that a patient does not have prostate cancer, he may worry more about developing prostate cancer in the future.
False-negative test results can occur.
Screening test results may appear to be normal even though prostate cancer is present. A man who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if he has symptoms.
False-positive test results can occur.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests, (such as biopsy) which also have risks.
Your doctor can advise you about your risk for prostate cancer and your need for screening tests.
Where can people get more information about prostate cancer screening?
For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 a.m. to 8:00 p.m., Eastern Time. Deaf and hard-of-hearing callers with TTY equipment may call 1-800-332-8615. A trained Cancer Information Specialist is available to answer your questions.
The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 8:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.
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Medically reviewed by Jay B. Zatzkin, MD; American Board of Internal Medicine with subspecialty in Medical Oncology
U.S. National Institutes of Health, National Cancer Institute, http://www.cancer.gov