Prostate-specific antigen, or PSA, is a protein naturally produced by the prostate gland in men. Because prostate cancer can increase the level of PSA in the blood, many doctors and professional organizations recommend that men over age 50 receive a PSA test in conjunction with a digital rectal exam to help detect the disease as early as possible. More recently, as the potential risks and limitations of PSA testing have become clear, some organizations have recommended that men learn about the risks and benefits of PSA testing before deciding whether to get tested themselves.
There is no hard-and-fast rule about what constitutes an “abnormal” PSA reading on a blood test. When interpreting the test results, doctors take a number of factors into consideration. One of these is the normal rise in PSA levels that often occurs as men age because of expected growth in benign prostatic tissue. However, some men’s prostates grow larger than others as they age, and there is no increase that definitively indicates cancer.
Most men with an elevated PSA level turn out not to have prostate cancer, according to the National Cancer Institute. Only about 25 percent of those who undergo a prostate biopsy – in which a small section of the prostate is removed and examined for signs of cancer – are found to have prostate cancer.
While PSA screening and digital rectal exams can help doctors find tumors that are too small to produce symptoms, many of those tumors are slow-growing and are unlikely to ever threaten a man’s life. Treating such cancers with surgery or other techniques carries a variety of risks, including a reduced ability to control urine flow, erectile dysfunction, or problems with bowel function. On the other hand, some prostate tumors uncovered by PSA testing may be so fast-growing that they’ve spread to other parts of the body by the time they’re detected.
Another problem is that PSA testing sometimes produces inaccurate results – suggesting cancer is present when in fact it is not, or indicating an absence of cancer when a tumor actually exists.
Men are advised to speak with their doctors about the risks and benefits of PSA testing before deciding whether to be tested. Such conversations are also important after testing, to help patients understand the meaning of the results and consider how to proceed.