PSA Blood Test
To rule out cancer, your doctor may recommend a PSA blood test. The amount of PSA, a protein produced by prostate cells, is often higher in the blood of men who have prostate cancer. However, an elevated level of PSA does not necessarily mean you have cancer. The Food and Drug Administration has approved a PSA test for use in conjunction with a DRE to help detect prostate cancer in men age 50 or older and for monitoring men with prostate cancer after treatment. However, much remains unknown about how to interpret the PSA test, its ability to discriminate between cancer and benign prostate conditions, and the best course of action if the PSA is high.
Because so many questions are unanswered, the relative magnitude of the test’s potential risks and benefits is unknown. When added to DRE screening, PSA enhances detection, but PSA tests are known to have relatively high false-positive rates, and they also may identify a greater number of medically insignificant tumors.
The PSA test first became available in the 1980s, and its use led to an increase in the detection of prostate cancer between 1986 and 1991. In the mid-1990s, deaths from prostate cancer began to decrease, and some observers credit PSA testing for this trend. Others, however, point out that statistical trends do not necessarily prove a cause-and-effect relationship. The benefits of prostate cancer screening are still being studied. The National Cancer Institute is conducting the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, or PLCO Trial, to determine whether certain screening tests reduce the number of deaths from these cancers. DRE and PSA exams are being studied to see whether yearly screening will decrease the risk of dying from prostate cancer.
Until a definitive answer is found, doctors and patients should weigh the benefits of PSA testing against the risks of follow-up diagnostic tests and cancer treatments. The procedures used to diagnose prostate cancer may cause significant side effects, including bleeding and infection. Treatment for prostate cancer often causes erectile dysfunction, or impotence, and may cause urinary incontinence.