Prostate-specific antigen, or PSA, is a protein produced by normal, as well as , cells of the prostate gland. For this test, a blood sample is sent to a laboratory for analysis. The blood level of PSA is often elevated in men with prostate cancer, and the PSA test was originally approved by the FDA in 1986 to monitor the progression of prostate cancer in men who had already been diagnosed with the disease. In 1994, the FDA approved the use of the PSA test in conjunction with a DRE to test men for prostate cancer. Men who report prostate symptoms often undergo PSA testing along with a DRE to help doctors determine the nature of the problem. The most frequent benign prostate conditions that cause an elevation in PSA level are prostatitis inflammation of the prostate and BPH enlargement of the prostate. There is no evidence that prostatitis or BPH leads to prostate cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well. Is the PSA test recommended for prostate cancer screening? Until about 2008, some doctors and professional organizations encouraged yearly PSA screening for men beginning at age 50. Some organizations recommended that men who are at higher risk of prostate cancer, including African American men and men whose father or brother had prostate cancer, begin screening at age 40 or 45. However, as more was learned about both the benefits and harms of prostate cancer screening, a number of organizations began to caution against routine population screening. Most organizations recommend that men who are considering PSA screening first discuss the risks and benefits with their doctors. Currently, provides coverage for an annual PSA test for all Medicare-eligible men age 50 and older. Many private insurers cover PSA screening as well. What is a normal PSA test result? There is no specific normal or abnormal level of PSA in the blood, and levels may vary over time in the same man. In the past, most doctors considered PSA levels of 4. Therefore, if a man had a PSA level above 4. However, more recent studies have shown that some men with PSA levels below 4. Prostate biopsies and prostate surgery also increase PSA level. PSA level may also vary somewhat across testing laboratories. Another complicating factor is that studies to establish the normal range of PSA levels have been conducted primarily in populations of white men. Although expert opinions vary, there is no clear consensus regarding the optimal PSA threshold for recommending a prostate biopsy for men of any racial or ethnic group. What if a screening test shows an elevated PSA level? If a man who has no symptoms of prostate cancer chooses to undergo prostate cancer screening and is found to have an elevated PSA level, the doctor may recommend another PSA test to confirm the original finding. If the PSA level is still high, the doctor may recommend that the man continue with PSA tests and DREs at regular intervals to watch for any changes over time. A urine test may be recommended to check for a urinary tract infection. The doctor may also recommend imaging tests, such as a , , or. If prostate cancer is suspected, the doctor will recommend a prostate biopsy. During this procedure, multiple samples of prostate tissue are collected by inserting hollow needles into the prostate and then withdrawing them. Most often, the needles are inserted through the wall of the rectum. A then examines the collected tissue under a. The doctor may use ultrasound to view the prostate during the biopsy, but ultrasound cannot be used alone to diagnose prostate cancer. What are some of the limitations and potential harms of the PSA test for prostate cancer screening? Detecting prostate cancer early may not reduce the chance of dying from prostate cancer. When used in screening, the PSA test can help detect small tumors that do not cause symptoms. The side effects of these treatments include urinary incontinence inability to control urine flow , problems with , erectile dysfunction loss of , or having erections that are inadequate for sexual intercourse , and infection. In addition, finding cancer early may not help a man who has a fast-growing or aggressive tumor that may have spread to other parts of the body before being detected. The PSA test may give false-positive or false-negative results. A false-positive test result may create for a man and his family and lead to additional medical procedures, such as a prostate biopsy, that can be harmful. Possible side effects of biopsies include serious infections, pain, and bleeding. Most men with an elevated PSA level turn out not to have prostate cancer; only about 25% of men who have a prostate biopsy due to an elevated PSA level actually are found to have prostate cancer when a biopsy is done. False-negative test results may give a man, his family, and his doctor false assurance that he does not have cancer, when he may in fact have a cancer that requires treatment. What research has been done to study prostate cancer screening? Several trials of prostate cancer screening have been carried out. One of the largest is the Prostate, Lung, Colorectal, and Ovarian PLCO Cancer Screening Trial, which NCI conducted to determine whether certain screening tests can help reduce the numbers of deaths from several common cancers. The PLCO investigators found that men who underwent annual prostate cancer screening had a higher of prostate cancer than men in the but the same rate of deaths from the disease. Overall, the results suggest that many men were treated for prostate cancers that would not have been detected in their lifetime without screening. Consequently, these men were exposed unnecessarily to the potential harms of treatment. A second large trial, the European Randomized Study of Screening for Prostate Cancer ERSPC , compared prostate cancer deaths in men randomly assigned to PSA-based screening or no screening. As in the PLCO, men in ERSPC who were screened for prostate cancer had a higher incidence of the disease than control men. In contrast to the PLCO, however, men who were screened had a lower rate of death from prostate cancer ,. A recent paper analyzed data from the PLCO using a complicated statistical model to account for the fact that some men in the PLCO trial who were assigned to the control group had nevertheless undergone PSA screening. This analysis suggested that the level of benefit in the PLCO and ERSPC trials were similar and that both trials were consistent with some reduction in prostate cancer death in association with prostate cancer screening. Such statistical modeling studies have important limitations and rely on unverified assumptions that can render their findings questionable or more suitable for further study than to serve as a basis for screening guidelines. More importantly, the model could not provide an assessment of the balance of benefits versus harms from screening. Of those, 80 would be treated either immediately or after a period of with surgery or radiation. How is the PSA test used in men who have been treated for prostate cancer? The PSA test is often used to monitor patients who have a history of prostate cancer to see if their cancer has recurred come back. However, a single elevated PSA measurement in a patient who has a history of prostate cancer does not always mean that the cancer has come back. A man who has been treated for prostate cancer should discuss an elevated PSA level with his doctor. The doctor may recommend repeating the PSA test or performing other tests to check for evidence of a recurrence. The doctor may look for a trend of rising PSA level over time rather than a single elevated PSA level. What does an increase in PSA level mean for a man who has been treated for prostate cancer? Additional treatment based on a single PSA test is not recommended. How are researchers trying to improve the PSA test? Scientists are investigating ways to improve the PSA test to give doctors the ability to better distinguish from conditions and slow-growing cancers from fast-growing, potentially lethal cancers. None has been proven to decrease the risk of death from prostate cancer. Some evidence suggests that a lower proportion of free PSA may be associated with more aggressive cancer. The blood level of PSA divided by the volume of the transition zone of the prostate. The transition zone is the interior part of the prostate that surrounds the. Some evidence suggests that this measure may be more accurate at detecting prostate cancer than the standard PSA test. However, age-specific reference ranges have not been generally favored because their use may delay the detection of prostate cancer in many men. Pro-PSA refers to several different inactive precursors of PSA. There is some evidence that pro-PSA is more strongly associated with prostate cancer than with. PSA exists in different structural forms called isoforms in the blood. The IsoPSA test, which measures the entire spectrum of PSA isoforms rather than the concentration of PSA in the blood, may improve the selection of men with prostate cancer for biopsy. Tests that combine measurements of PSA in blood with measurements of other linked to prostate cancer in blood or urine are being studied for their ability to distinguish high-risk disease. These other biomarkers include kallikrein-related peptidase 2, prostate cancer antigen 3 PCA3 , and the TMPRSS2-ERG. New England Journal of Medicine 2004;350 22 :2239-2246. Prostate-specific-antigen testing for early diagnosis of prostate cancer. New England Journal of Medicine 2001;344 18 :1373-1377. Extended mortality results for prostate cancer screening in the PLCO trial with median follow-up of 15 years. Cancer 2017; 123 4 :592-599. Prostate-cancer mortality at 11 years of follow-up. New England Journal of Medicine 2012;366 11 :981-990. Screening and prostate cancer mortality: Results of the European Randomised Study of Screening for Prostate Cancer ERSPC at 13 years of follow-up. Lancet 2014; 384: 2027-2035. Reconciling the effects of screening on prostate cancer mortality in the ERSPC and PLCO trials. Annals of Internal Medicine 2017; 167 7 :449-455. Preventive Health Services Task Force. Accessed April 24, 2017. The single-parameter, structure-based IsoPSA assay demonstrates improved diagnostic accuracy for detection of any prostate cancer and high-grade prostate cancer compared to a concentration-based assay of total prostate-specific antigen: A preliminary report. European Urology 2017; S0302-2838 17 30236-1. If you would like to reproduce some or all of this content, see for guidance about copyright and permissions. In the case of permitted digital reproduction, please credit the National Cancer Institute as the source and link to the original NCI product using the original product's title; e. All comments must follow our.
