Screening for cancer is examination (or testing) of people for early stages in the development of cancer even though they have no symptoms. Scientists have studied patterns of cancer in the population to learn which people are more likely to get certain types of cancer. They have also studied what things around us and what things we do in our lives may cause cancer. This information sometimes helps doctors recommend who should be screened for certain types of cancer, what types of screening tests people should have, and how often these tests should be done. Not all screening tests are helpful, and most have risks such as bleeding or infection due to a biopsy of the prostate for an abnormal PSA blood test. For this reason, scientists at the National Cancer Institute are studying many screening tests to find out how useful they are and to determine the relative benefits and harms.
If your doctor suggests certain cancer screening tests as part of your health care plan, this does not mean he or she thinks you have cancer. Screening tests are done when you have no symptoms. Since decisions about screening can be difficult, you may want to discuss them with your doctor and ask questions about the potential benefits and risks of screening tests and whether they have been proven to decrease the risk of dying from cancer.
If your doctor suspects that you may have cancer, he or she will order certain tests to see whether you do. These are called diagnostic tests. Some tests are used for diagnostic purposes, but are not suitable for screening people who have no symptoms.
The purposes of this summary on prostate cancer screening are to:
You can talk to your doctor or health care professional about cancer screening and whether it would be likely to help you.
The prostate is a gland in males that is involved in the production of semen. It is located between the bladder and the rectum. The normal prostate gland is the size of a walnut and surrounds the urethra, the tube that carries urine from the bladder.
Prostate cancer is the most common cancer in North American men (other than skin cancer). It is the second leading cause of cancer death in men (after lung cancer).
Incidence of a disease is the rate at which new cases of that disease are diagnosed in a given year among people at risk for that disease (for example, men in the case of prostate cancer). The incidence is, therefore, the average risk of being diagnosed with the disease that year. From the late 1980s through the early 1990s, the incidence of prostate cancer rose rapidly, followed by an equally rapid fall.
Mortality rate of a disease is the chance of dying of that disease in a given year among people at risk for that disease. The mortality rate is, therefore, the average risk of dying of that disease in that year. The mortality rates of prostate cancer followed a similar pattern to the incidence rates mentioned above, but to a lesser degree.
Anything that increases a person’s chance of developing a disease is called a risk factor. Some of these risk factors for prostate cancer are as follows:
Age: Prostate cancer is rarely seen in men younger than 50 years old. The chance of developing prostate cancer increases as men get older.
Race: Black males are more likely to develop prostate cancer than white males. Black males are also more likely to die of prostate cancer than white males.
Family History of Prostate Cancer: A man whose father, brother, or son has had prostate cancer has a higher-than-average risk of developing prostate cancer.
Other potential risk factors include alcohol consumption, vitamin or mineral interactions, and other dietary habits.
Digital Rectal Examination: A digital rectal examination (DRE) is performed by a doctor during a regular office visit. For this examination, the doctor inserts a gloved finger into the rectum and feels the prostate gland through the rectal wall to check for bumps or abnormal areas. Although this test has been used for many years, whether DRE is effective in decreasing the number of deaths from prostate cancer has not been determined.
Transrectal Ultrasonography: During this examination, high-frequency sound waves are sent out by a probe about the size of the index finger, which is inserted into the rectum. The waves bounce off the prostate gland and produce echoes that a computer uses to create a picture called a sonogram. Doctors examine the sonogram for echoes that might represent abnormal areas. Whether ultrasonography is effective in decreasing mortality from prostate cancer has not been determined.
PSA: For this test, a blood sample is drawn and the amount of prostate- specific antigen (PSA) present is determined in a laboratory. PSA is a marker that, if present in higher than average amounts, may indicate prostate cancer cells. However, PSA levels may also be higher in men who have noncancerous prostate conditions. Scientists are studying ways to improve the reliability of the PSA test.
Because unnecessary treatment due to false screening results could be harmful, research is being done to determine the most reliable method for prostate cancer screening. For example, scientists at the National Cancer Institute are studying the value of early detection by DRE and PSA on reducing the number of deaths caused by prostate cancer.
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Editorial changes were made to this summary.
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Web sites and Organizations
The NCI's Cancer.gov Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. There are also many other places where people can get materials and information about cancer treatment and services. Local hospitals may have information on local and regional agencies that offer information about finances, getting to and from treatment, receiving care at home, and dealing with problems associated with cancer treatment.
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PDQ is a comprehensive cancer database available on Cancer.gov.
PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at Cancer.gov, the NCI's Web site. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.
PDQ contains cancer information summaries.
The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.
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PDQ also contains information on clinical trials.
People who are at high risk for a certain type of cancer may want to take part in a clinical trial. A clinical trial is a study to answer a scientific question, such as whether a method of finding cancer earlier can help people to live longer. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients and those who are at risk for cancer. During screening clinical trials, information is collected about screening methods, the risks involved, and how well they do or do not work. If a clinical trial shows that a new method is better than one currently being used, the new method may become "standard."
Listings of clinical trials are included in PDQ and are available online at Cancer.gov. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.Physicians version: CDR0000062755