Screening refers to testing to find a disease such as cancer in people who do not have symptoms of that disease. For some types of cancer, screening can help find cancers in an early stage when they are more easily cured.
There are several factors to take into account when screening for prostate cancer. These include a man’s age, overall health and any risk factors he may have.
Most doctors recommend that screening should begin at the following ages:
• age 40 for men who have several first-degree relatives who were diagnosed with prostate cancer when they were younger than age 65
• age 45 for men at high risk such as African American men, and men who have a father, brother or son who were diagnosed with prostate cancer when they were younger than 65
• age 50 for men who are at average risk of prostate cancer and are expected to live at least 10 more years
There are two main tests used to screen for prostate cancer:
• Prostate-specific antigen (PSA) test – During this test a blood sample is drawn from a vein in the arm and analyzed for PSA, which is a substance produced by the prostate gland. An elevated level of PSA in the bloodstream can be an indication of prostate infection, inflammation, enlargement or cancer.
• Digital rectal exam (DRE) - During a DRE, a doctor inserts a gloved, lubricated finger into the rectum to examine the prostate, which is adjacent to the rectum. If the doctor finds any abnormalities in the texture, shape or size of the gland, they may be an indication of prostate cancer.
DRE is less effective than the PSA blood test in finding prostate cancer but it can sometimes find cancers in men with normal PSA levels. The DRE can also be used once a man is known to have prostate cancer to try to determine if it may have spread to nearby tissues, and to detect cancer that has come back after treatment.
PSA testing combined with DRE can help identify prostate cancers at their earliest stages. If the results of either one of these tests are abnormal, further testing should be done to determine whether cancer is present. If prostate cancer is found as a result of screening with the PSA test or DRE, it will likely be at an early, more treatable stage than if no screening were done.
These tests are not always 100 percent accurate, however. They both can produce abnormal results when cancer is not present. This is known as a false positive. Also, normal results can occur when cancer is present. This is known as a false negative.
Additionally, an elevated PSA level can be a result of other conditions such as non-cancerous enlargement of the prostate, age, infection or inflammation of the prostate, ejaculation (which can cause the PSA to go up for a short period of time), riding a bicycle and certain urologic procedures.
PSA levels also can go down even when cancer is present due to certain medications, herbal mixtures, dietary supplements, certain steroids, obesity and aspirin.
While the PSA test mainly is used for the early detection of prostate cancer, once prostate cancer is diagnosed, it can also be used to help determine the following:
• if additional tests such as CT scans or bone scans are needed
• if the cancer is has spread beyond the prostate
• if treatment is working
• if active treatment should be considered when a patient has chosen a "watchful waiting" approach to treatment
Learn more about prostate cancer